diff --git a/cmd/dashboard/controller/controller.go b/cmd/dashboard/controller/controller.go
index 1823d2c4..a3dd50b0 100644
--- a/cmd/dashboard/controller/controller.go
+++ b/cmd/dashboard/controller/controller.go
@@ -57,6 +57,9 @@ func routers(r *gin.Engine, frontendDist fs.FS) {
 	if err := authMiddleware.MiddlewareInit(); err != nil {
 		log.Fatal("authMiddleware.MiddlewareInit Error:" + err.Error())
 	}
+	// Signature-only view of the auth middleware for IsDashboardCredential:
+	// same key and pinned algorithm, claims validation deliberately skipped.
+	dashboardCredentialJWTParser = newDashboardCredentialJWTParser(authMiddleware)
 	// /mcp — Model Context Protocol endpoint, authenticated by PAT only (闸 1 + 闸 2)。
 	// 不放在 /api/v1 下：MCP client 配置 URL 更短，且 MCP transport 协议演进与 REST API
 	// 解耦。鉴权一律走 apiTokenAuthMiddleware；不接受 JWT 以避免浏览器误触。
diff --git a/cmd/dashboard/controller/dashboard_credential.go b/cmd/dashboard/controller/dashboard_credential.go
new file mode 100644
index 00000000..00af53ea
--- /dev/null
+++ b/cmd/dashboard/controller/dashboard_credential.go
@@ -0,0 +1,118 @@
+package controller
+
+import (
+	"errors"
+	"log"
+	"strings"
+
+	jwt "github.com/golang-jwt/jwt/v4"
+	"gorm.io/gorm"
+
+	ginjwt "github.com/appleboy/gin-jwt/v2"
+	"github.com/nezhahq/nezha/model"
+	"github.com/nezhahq/nezha/service/singleton"
+)
+
+// dashboardCredentialJWTParser verifies that a JWT was signed by this
+// dashboard. It is derived from the auth middleware created in routers() and
+// exists only for IsDashboardCredential; it must never authenticate dashboard
+// requests on its own.
+var dashboardCredentialJWTParser *ginjwt.GinJWTMiddleware
+
+// newDashboardCredentialJWTParser derives a signature-only parser from the
+// dashboard auth middleware. It keeps the exact key value and the pinned HS256
+// signing algorithm of initParams() — there is no second read of
+// singleton.Conf.JWTSecretKey — and disables claims validation so expiry does
+// not change the verdict: an expired token is still proof the dashboard issued
+// it, and keeping expired dashboard tokens out of the NAT tunnel prevents a
+// careless backend from treating "any JWT" as its own credential. The live
+// auth middleware keeps full claims validation; dashboard authentication is
+// not relaxed by this parser in any way.
+func newDashboardCredentialJWTParser(authMiddleware *ginjwt.GinJWTMiddleware) *ginjwt.GinJWTMiddleware {
+	parser := *authMiddleware
+	parser.ParseOptions = []jwt.ParserOption{jwt.WithoutClaimsValidation()}
+	return &parser
+}
+
+// IsDashboardCredential reports whether an Authorization header value was
+// issued by this dashboard: a panel-signed JWT or a panel API token (PAT).
+//
+// NAT ingress uses this to enforce the tunnel credential invariant: values
+// classified as dashboard-issued are stripped before the request is tunneled
+// to the agent, while foreign credentials are forwarded untouched because the
+// NAT backend may authenticate with credentials of its own.
+//
+// Decision policy mirrors the dashboard's own auth middlewares: only the
+// case-sensitive "Bearer " scheme is considered; the value after the scheme is
+// classified by IsDashboardCredentialValue, which is also the entry point for
+// the panel's scheme-less TokenLookup channels. Only a deterministic proof
+// that the value was not issued by this dashboard (scheme mismatch, unknown
+// PAT hash, failed signature verification) returns false.
+func IsDashboardCredential(authz string) bool {
+	raw := strings.TrimSpace(authz)
+	if !strings.HasPrefix(raw, "Bearer ") {
+		return false
+	}
+	return IsDashboardCredentialValue(strings.TrimPrefix(raw, "Bearer "))
+}
+
+// IsDashboardCredentialValue reports whether a raw credential value — the part
+// after the "Bearer " scheme, exactly as the panel's other TokenLookup
+// channels carry it (the ?token= query parameter and the nz-jwt cookie, see
+// initParams) — was issued by this dashboard: a panel-signed JWT or a panel
+// API token (PAT).
+//
+// Failure policy is identical to IsDashboardCredential: whenever the
+// classification cannot be completed (parser or config not ready, database
+// failure) the value is conservatively reported as a dashboard credential so
+// the caller strips it; only a deterministic proof that the value was not
+// issued by this dashboard (unknown PAT hash, failed signature verification)
+// returns false.
+func IsDashboardCredentialValue(value string) bool {
+	plaintext := strings.TrimSpace(value)
+	if strings.HasPrefix(plaintext, model.APITokenPrefix) {
+		return isDashboardAPIToken(plaintext)
+	}
+	return isDashboardSignedJWT(plaintext)
+}
+
+// isDashboardAPIToken resolves a PAT-shaped value against the api_tokens
+// table. The plaintext token is only ever hashed here; it is never logged.
+func isDashboardAPIToken(plaintext string) bool {
+	if singleton.DB == nil {
+		logDashboardCredentialUnclassifiable("api token lookup unavailable")
+		return true
+	}
+	var tok model.APIToken
+	err := singleton.DB.Where("token_hash = ?", model.HashAPIToken(plaintext)).First(&tok).Error
+	if err == nil {
+		return true
+	}
+	if errors.Is(err, gorm.ErrRecordNotFound) {
+		// Deterministic proof the token was not issued by this dashboard:
+		// forwarding it leaks nothing the dashboard ever validated.
+		return false
+	}
+	logDashboardCredentialUnclassifiable("api token lookup failed")
+	return true
+}
+
+// isDashboardSignedJWT verifies the token signature with the dashboard's
+// pinned algorithm and key. Claims validation is disabled on purpose (see
+// newDashboardCredentialJWTParser): expiry does not change who issued the
+// token.
+func isDashboardSignedJWT(token string) bool {
+	if dashboardCredentialJWTParser == nil {
+		// routers() has not run yet (startup incomplete): fail closed.
+		logDashboardCredentialUnclassifiable("dashboard credential parser unavailable")
+		return true
+	}
+	_, err := dashboardCredentialJWTParser.ParseTokenString(token)
+	return err == nil
+}
+
+// logDashboardCredentialUnclassifiable records a classification failure. The
+// Authorization value itself is never included in the message.
+func logDashboardCredentialUnclassifiable(reason string) {
+	log.Printf("NEZHA>> NAT ingress: Authorization value could not be classified (%s); stripping it as a precaution", reason)
+}
diff --git a/cmd/dashboard/controller/dashboard_credential_nat_flow_test.go b/cmd/dashboard/controller/dashboard_credential_nat_flow_test.go
new file mode 100644
index 00000000..26a8f6ff
--- /dev/null
+++ b/cmd/dashboard/controller/dashboard_credential_nat_flow_test.go
@@ -0,0 +1,250 @@
+package controller
+
+import (
+	"bufio"
+	"bytes"
+	"context"
+	"io"
+	"net"
+	"net/http"
+	"net/url"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/goccy/go-json"
+	"github.com/stretchr/testify/require"
+	"google.golang.org/grpc/metadata"
+
+	"github.com/nezhahq/nezha/cmd/dashboard/rpc"
+	"github.com/nezhahq/nezha/model"
+	"github.com/nezhahq/nezha/proto"
+	rpcService "github.com/nezhahq/nezha/service/rpc"
+	"github.com/nezhahq/nezha/service/singleton"
+)
+
+// setupNATFlowTest extends setupDashboardCredentialTest with the minimal
+// ServeNAT environment: a registered server with a task stream and a fresh
+// handler singleton, mirroring the rpc package's serveNAT fixture.
+func setupNATFlowTest(t *testing.T) (*rpcService.NezhaHandler, *model.Server, *natFlowTaskStream) {
+	t.Helper()
+	setupDashboardCredentialTest(t)
+
+	require.NoError(t, singleton.DB.AutoMigrate(&model.Server{}))
+	originalServerShared, originalHandler := singleton.ServerShared, rpcService.NezhaHandlerSingleton
+	t.Cleanup(func() {
+		singleton.ServerShared, rpcService.NezhaHandlerSingleton = originalServerShared, originalHandler
+	})
+
+	serverRow := &model.Server{Common: model.Common{ID: 7}, UUID: "nat-credential-flow-test", Name: "nat-credential-flow-test"}
+	require.NoError(t, singleton.DB.Create(serverRow).Error)
+	singleton.ServerShared = singleton.NewServerClass()
+	handler := rpcService.NewNezhaHandler()
+	rpcService.NezhaHandlerSingleton = handler
+
+	server, ok := singleton.ServerShared.Get(serverRow.ID)
+	require.True(t, ok)
+	taskStream := &natFlowTaskStream{}
+	server.SetTaskStream(taskStream)
+
+	// Wire the gate exactly as cmd/dashboard/main.go does, with the real
+	// classifiers built by setupDashboardCredentialTest.
+	rpc.SetNATDashboardCredentialGate(IsDashboardCredential, IsDashboardCredentialValue)
+	t.Cleanup(func() { rpc.SetNATDashboardCredentialGate(nil, nil) })
+
+	return handler, server, taskStream
+}
+
+// TestServeNATWithRealClassifierStripsDashboardCredentialsFromAllChannels pins
+// the main() wiring contract end to end: with the real classifiers wired as
+// main() does, ServeNAT forwards a request whose dashboard-issued credentials
+// — Authorization header, ?token= query parameter, nz-jwt cookie — are all
+// stripped, while foreign values and untouched query/cookie data survive
+// byte-for-byte.
+func TestServeNATWithRealClassifierStripsDashboardCredentialsFromAllChannels(t *testing.T) {
+	handler, server, taskStream := setupNATFlowTest(t)
+
+	dashboardJWT := mintDashboardCredentialJWT(t, time.Hour)
+	foreignJWT := mintForeignJWT(t)
+	// No api_tokens row hashes to this PAT, so the classifier proves it was
+	// not issued by this dashboard and it must survive the tunnel.
+	foreignPAT := model.APITokenPrefix + "foreign-issued-pat"
+	dashboardPAT := model.APITokenPrefix + "dashboard-issued-pat"
+	require.NoError(t, singleton.DB.Create(&model.APIToken{
+		UserID:    1,
+		Name:      "nat-flow",
+		TokenHash: model.HashAPIToken(dashboardPAT),
+	}).Error)
+
+	connection := &natFlowConn{closed: make(chan struct{})}
+	agent := &natFlowAgent{writeDone: make(chan struct{})}
+	writer := &natFlowWriter{conn: connection}
+	request := &http.Request{
+		Method: http.MethodPost,
+		URL: &url.URL{Path: "/nat", RawQuery: "keep=1&token=" + dashboardJWT + "&token=" + url.QueryEscape(foreignJWT) +
+			"&token=" + foreignPAT + "&token=" + dashboardPAT},
+		Header: make(http.Header),
+		Body:   http.NoBody,
+	}
+	request.Header.Set("Authorization", "Bearer "+dashboardJWT)
+	request.Header.Set("Cookie", "sid=abc; nz-jwt="+dashboardJWT+"; nz-jwt="+foreignJWT+"; nz-jwt="+foreignPAT)
+	request.Header.Set("X-Ordinary-Nat", "ordinary")
+	taskStream.onSend = func(task *proto.Task) error {
+		var nat model.TaskNAT
+		if err := json.Unmarshal([]byte(task.Data), &nat); err != nil {
+			return err
+		}
+		return handler.AgentConnected(nat.StreamID, agent)
+	}
+
+	done := make(chan struct{})
+	go func() {
+		rpc.ServeNAT(writer, request, &model.NAT{ServerID: server.ID, Host: "target.example"})
+		close(done)
+	}()
+	select {
+	case <-agent.writeDone:
+	case <-time.After(time.Second):
+		t.Fatal("agent did not receive the transferred NAT request")
+	}
+	require.NoError(t, connection.Close())
+	select {
+	case <-done:
+	case <-time.After(time.Second):
+		t.Fatal("ServeNAT did not finish")
+	}
+
+	forwarded := string(agent.writtenBytes())
+	// Dashboard credentials are gone from every channel.
+	require.NotContains(t, forwarded, "Authorization:")
+	require.NotContains(t, forwarded, dashboardJWT)
+	require.NotContains(t, forwarded, dashboardPAT)
+	// Foreign credentials and untouched data survive byte-for-byte.
+	require.Contains(t, forwarded, "POST /nat?keep=1&token="+url.QueryEscape(foreignJWT)+"&token="+foreignPAT+" HTTP/1.1")
+	require.Contains(t, forwarded, "Cookie: sid=abc; nz-jwt="+foreignJWT+"; nz-jwt="+foreignPAT)
+	require.Contains(t, forwarded, "X-Ordinary-Nat: ordinary")
+}
+
+// TestServeNATWithRealClassifierKeepsForeignCredentials pins that the real
+// classifier deterministically proves foreign values were not issued by this
+// dashboard and leaves every channel untouched.
+func TestServeNATWithRealClassifierKeepsForeignCredentials(t *testing.T) {
+	handler, server, taskStream := setupNATFlowTest(t)
+
+	foreignJWT := mintForeignJWT(t)
+	connection := &natFlowConn{closed: make(chan struct{})}
+	agent := &natFlowAgent{writeDone: make(chan struct{})}
+	writer := &natFlowWriter{conn: connection}
+	request := &http.Request{
+		Method: http.MethodPost,
+		URL:    &url.URL{Path: "/nat", RawQuery: "token=" + foreignJWT},
+		Header: make(http.Header),
+		Body:   http.NoBody,
+	}
+	request.Header.Set("Authorization", "Bearer "+foreignJWT)
+	request.Header.Set("Cookie", "nz-jwt="+foreignJWT)
+	taskStream.onSend = func(task *proto.Task) error {
+		var nat model.TaskNAT
+		if err := json.Unmarshal([]byte(task.Data), &nat); err != nil {
+			return err
+		}
+		return handler.AgentConnected(nat.StreamID, agent)
+	}
+
+	done := make(chan struct{})
+	go func() {
+		rpc.ServeNAT(writer, request, &model.NAT{ServerID: server.ID, Host: "target.example"})
+		close(done)
+	}()
+	select {
+	case <-agent.writeDone:
+	case <-time.After(time.Second):
+		t.Fatal("agent did not receive the transferred NAT request")
+	}
+	require.NoError(t, connection.Close())
+	select {
+	case <-done:
+	case <-time.After(time.Second):
+		t.Fatal("ServeNAT did not finish")
+	}
+
+	forwarded := string(agent.writtenBytes())
+	require.Contains(t, forwarded, "POST /nat?token="+foreignJWT+" HTTP/1.1")
+	require.Contains(t, forwarded, "Authorization: Bearer "+foreignJWT)
+	require.Contains(t, forwarded, "Cookie: nz-jwt="+foreignJWT)
+}
+
+type natFlowTaskStream struct {
+	onSend func(*proto.Task) error
+}
+
+func (stream *natFlowTaskStream) Send(task *proto.Task) error {
+	if stream.onSend != nil {
+		return stream.onSend(task)
+	}
+	return nil
+}
+func (*natFlowTaskStream) Recv() (*proto.TaskResult, error) { return nil, io.EOF }
+func (*natFlowTaskStream) SetHeader(metadata.MD) error      { return nil }
+func (*natFlowTaskStream) SendHeader(metadata.MD) error     { return nil }
+func (*natFlowTaskStream) SetTrailer(metadata.MD)           {}
+func (*natFlowTaskStream) Context() context.Context         { return context.Background() }
+func (*natFlowTaskStream) SendMsg(any) error                { return nil }
+func (*natFlowTaskStream) RecvMsg(any) error                { return io.EOF }
+
+type natFlowWriter struct{ conn *natFlowConn }
+
+func (writer *natFlowWriter) Header() http.Header            { return http.Header{} }
+func (writer *natFlowWriter) Write(data []byte) (int, error) { return len(data), nil }
+func (writer *natFlowWriter) WriteHeader(int)                {}
+func (writer *natFlowWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
+	go func() { _, _ = writer.conn.Read(make([]byte, 1)) }()
+	return writer.conn, bufio.NewReadWriter(bufio.NewReader(writer.conn), bufio.NewWriter(writer.conn)), nil
+}
+
+type natFlowConn struct {
+	closed    chan struct{}
+	closeOnce sync.Once
+}
+
+func (conn *natFlowConn) Read([]byte) (int, error) {
+	<-conn.closed
+	return 0, io.EOF
+}
+func (conn *natFlowConn) Write(data []byte) (int, error) { return len(data), nil }
+func (conn *natFlowConn) Close() error {
+	conn.closeOnce.Do(func() { close(conn.closed) })
+	return nil
+}
+func (conn *natFlowConn) LocalAddr() net.Addr              { return natFlowAddr{} }
+func (conn *natFlowConn) RemoteAddr() net.Addr             { return natFlowAddr{} }
+func (conn *natFlowConn) SetDeadline(time.Time) error      { return nil }
+func (conn *natFlowConn) SetReadDeadline(time.Time) error  { return nil }
+func (conn *natFlowConn) SetWriteDeadline(time.Time) error { return nil }
+
+type natFlowAddr struct{}
+
+func (natFlowAddr) Network() string { return "test" }
+func (natFlowAddr) String() string  { return "test" }
+
+type natFlowAgent struct {
+	mu        sync.Mutex
+	written   bytes.Buffer
+	writeDone chan struct{}
+	once      sync.Once
+}
+
+func (agent *natFlowAgent) Read([]byte) (int, error) { return 0, io.EOF }
+func (agent *natFlowAgent) Write(data []byte) (int, error) {
+	agent.mu.Lock()
+	agent.written.Write(data)
+	agent.mu.Unlock()
+	agent.once.Do(func() { close(agent.writeDone) })
+	return len(data), nil
+}
+func (*natFlowAgent) Close() error { return nil }
+func (agent *natFlowAgent) writtenBytes() []byte {
+	agent.mu.Lock()
+	defer agent.mu.Unlock()
+	return append([]byte(nil), agent.written.Bytes()...)
+}
diff --git a/cmd/dashboard/controller/dashboard_credential_test.go b/cmd/dashboard/controller/dashboard_credential_test.go
new file mode 100644
index 00000000..fbfe47ec
--- /dev/null
+++ b/cmd/dashboard/controller/dashboard_credential_test.go
@@ -0,0 +1,196 @@
+package controller
+
+import (
+	"bytes"
+	"log"
+	"testing"
+	"time"
+
+	jwt "github.com/appleboy/gin-jwt/v2"
+	"github.com/stretchr/testify/require"
+	"gorm.io/driver/sqlite"
+	"gorm.io/gorm"
+
+	"github.com/nezhahq/nezha/model"
+	"github.com/nezhahq/nezha/service/singleton"
+)
+
+func setupDashboardCredentialTest(t *testing.T) {
+	t.Helper()
+	originalConf, originalDB, originalParser := singleton.Conf, singleton.DB, dashboardCredentialJWTParser
+	t.Cleanup(func() {
+		singleton.Conf, singleton.DB, dashboardCredentialJWTParser = originalConf, originalDB, originalParser
+	})
+
+	singleton.Conf = &singleton.ConfigClass{Config: &model.Config{}}
+	singleton.Conf.JWTSecretKey = "dashboard-credential-classification-test-key"
+	singleton.Conf.JWTTimeout = 1
+
+	db, err := gorm.Open(sqlite.Open(":memory:"), &gorm.Config{})
+	require.NoError(t, err)
+	sqlDB, err := db.DB()
+	require.NoError(t, err)
+	t.Cleanup(func() { _ = sqlDB.Close() })
+	require.NoError(t, db.AutoMigrate(&model.APIToken{}))
+	singleton.DB = db
+
+	// Same construction path as routers(): jwt.New(initParams()).
+	authMiddleware, err := jwt.New(initParams())
+	require.NoError(t, err)
+	dashboardCredentialJWTParser = newDashboardCredentialJWTParser(authMiddleware)
+}
+
+// mintDashboardCredentialJWT signs a JWT with the dashboard key through
+// initParams(), the same key source the production verifier uses. A negative
+// timeout mints an already-expired token.
+func mintDashboardCredentialJWT(t *testing.T, timeout time.Duration) string {
+	t.Helper()
+	params := initParams()
+	params.Timeout = timeout
+	mw, err := jwt.New(params)
+	require.NoError(t, err)
+	token, _, err := mw.TokenGenerator(nil)
+	require.NoError(t, err)
+	return token
+}
+
+func mintForeignJWT(t *testing.T) string {
+	t.Helper()
+	params := initParams()
+	params.Key = []byte("foreign-signing-key-not-held-by-the-dashboard")
+	mw, err := jwt.New(params)
+	require.NoError(t, err)
+	token, _, err := mw.TokenGenerator(nil)
+	require.NoError(t, err)
+	return token
+}
+
+func TestIsDashboardCredentialClassification(t *testing.T) {
+	setupDashboardCredentialTest(t)
+
+	dashboardJWT := mintDashboardCredentialJWT(t, time.Hour)
+	expiredDashboardJWT := mintDashboardCredentialJWT(t, -time.Hour)
+	foreignJWT := mintForeignJWT(t)
+
+	dashboardPAT := model.APITokenPrefix + "dashboard-credential-pat"
+	require.NoError(t, singleton.DB.Create(&model.APIToken{
+		UserID:    1,
+		Name:      "nat-classification",
+		TokenHash: model.HashAPIToken(dashboardPAT),
+	}).Error)
+
+	t.Run("dashboard signed jwt is a dashboard credential", func(t *testing.T) {
+		require.True(t, IsDashboardCredential("Bearer "+dashboardJWT))
+	})
+
+	t.Run("expired dashboard signed jwt is still a dashboard credential", func(t *testing.T) {
+		// Signature verification ignores exp on purpose: an expired token is
+		// still proof the dashboard issued it.
+		require.True(t, IsDashboardCredential("Bearer "+expiredDashboardJWT))
+	})
+
+	t.Run("dashboard api token is a dashboard credential", func(t *testing.T) {
+		require.True(t, IsDashboardCredential("Bearer "+dashboardPAT))
+	})
+
+	t.Run("foreign signed jwt is not a dashboard credential", func(t *testing.T) {
+		require.False(t, IsDashboardCredential("Bearer "+foreignJWT))
+	})
+
+	t.Run("unknown api token is not a dashboard credential", func(t *testing.T) {
+		require.False(t, IsDashboardCredential("Bearer "+model.APITokenPrefix+"unknown-to-the-dashboard"))
+	})
+
+	t.Run("random string is not a dashboard credential", func(t *testing.T) {
+		require.False(t, IsDashboardCredential("Bearer random-not-a-token"))
+	})
+
+	t.Run("non bearer scheme is not a dashboard credential", func(t *testing.T) {
+		require.False(t, IsDashboardCredential("Basic "+dashboardJWT))
+		// Scheme matching is case-sensitive, as in both dashboard auth middlewares.
+		require.False(t, IsDashboardCredential("bearer "+dashboardJWT))
+	})
+
+	t.Run("empty or missing header is not a dashboard credential", func(t *testing.T) {
+		require.False(t, IsDashboardCredential(""))
+		require.False(t, IsDashboardCredential("Bearer "))
+	})
+}
+
+// TestIsDashboardCredentialValueClassification pins the scheme-less classifier
+// that backs IsDashboardCredential and drives the ?token= query parameter and
+// nz-jwt cookie channels at NAT ingress (see IsDashboardCredentialValue).
+func TestIsDashboardCredentialValueClassification(t *testing.T) {
+	setupDashboardCredentialTest(t)
+
+	dashboardJWT := mintDashboardCredentialJWT(t, time.Hour)
+	expiredDashboardJWT := mintDashboardCredentialJWT(t, -time.Hour)
+	foreignJWT := mintForeignJWT(t)
+
+	dashboardPAT := model.APITokenPrefix + "dashboard-credential-value-pat"
+	require.NoError(t, singleton.DB.Create(&model.APIToken{
+		UserID:    1,
+		Name:      "nat-value-classification",
+		TokenHash: model.HashAPIToken(dashboardPAT),
+	}).Error)
+
+	t.Run("dashboard signed jwt is a dashboard credential", func(t *testing.T) {
+		require.True(t, IsDashboardCredentialValue(dashboardJWT))
+	})
+	t.Run("expired dashboard signed jwt is still a dashboard credential", func(t *testing.T) {
+		require.True(t, IsDashboardCredentialValue(expiredDashboardJWT))
+	})
+	t.Run("dashboard api token is a dashboard credential", func(t *testing.T) {
+		require.True(t, IsDashboardCredentialValue(dashboardPAT))
+	})
+	t.Run("foreign signed jwt is not a dashboard credential", func(t *testing.T) {
+		require.False(t, IsDashboardCredentialValue(foreignJWT))
+	})
+	t.Run("unknown api token is not a dashboard credential", func(t *testing.T) {
+		require.False(t, IsDashboardCredentialValue(model.APITokenPrefix+"unknown-to-the-dashboard"))
+	})
+	t.Run("random string is not a dashboard credential", func(t *testing.T) {
+		require.False(t, IsDashboardCredentialValue("random-not-a-token"))
+	})
+	t.Run("empty value is not a dashboard credential", func(t *testing.T) {
+		require.False(t, IsDashboardCredentialValue(""))
+	})
+	t.Run("bearer scheme is not part of the value contract", func(t *testing.T) {
+		// The query and cookie channels carry the bare value; a value that
+		// itself starts with "Bearer " is not something the panel issues and
+		// fails signature verification.
+		require.False(t, IsDashboardCredentialValue("Bearer "+dashboardJWT))
+	})
+}
+
+func TestIsDashboardCredentialFailsClosedWhenParserUnavailable(t *testing.T) {
+	setupDashboardCredentialTest(t)
+	dashboardCredentialJWTParser = nil
+
+	token := mintDashboardCredentialJWT(t, time.Hour)
+	require.True(t, IsDashboardCredential("Bearer "+token))
+}
+
+func TestIsDashboardCredentialFailsClosedWhenAPITokenLookupUnavailable(t *testing.T) {
+	setupDashboardCredentialTest(t)
+	singleton.DB = nil
+
+	require.True(t, IsDashboardCredential("Bearer "+model.APITokenPrefix+"unresolvable"))
+}
+
+func TestIsDashboardCredentialFailsClosedOnDatabaseError(t *testing.T) {
+	setupDashboardCredentialTest(t)
+	sqlDB, err := singleton.DB.DB()
+	require.NoError(t, err)
+	require.NoError(t, sqlDB.Close())
+
+	var logs bytes.Buffer
+	originalOutput := log.Writer()
+	log.SetOutput(&logs)
+	t.Cleanup(func() { log.SetOutput(originalOutput) })
+
+	plaintext := model.APITokenPrefix + "unresolvable-after-db-failure"
+	require.True(t, IsDashboardCredential("Bearer "+plaintext))
+	// The credential content itself must never reach the log.
+	require.NotContains(t, logs.String(), plaintext)
+}
diff --git a/cmd/dashboard/dashboard_credential_wiring_test.go b/cmd/dashboard/dashboard_credential_wiring_test.go
new file mode 100644
index 00000000..95be89ff
--- /dev/null
+++ b/cmd/dashboard/dashboard_credential_wiring_test.go
@@ -0,0 +1,27 @@
+package main
+
+import (
+	"testing"
+
+	"github.com/nezhahq/nezha/cmd/dashboard/rpc"
+)
+
+// TestWireNATDashboardCredentialGate pins the NAT ingress wiring contract:
+// main() must connect the real dashboard-credential classifiers
+// (controller.IsDashboardCredential / controller.IsDashboardCredentialValue)
+// through wireNATDashboardCredentialGate before any listener serves traffic.
+// That the wired functions really classify per channel is pinned end to end
+// by the controller package's real-classifier NAT flow test.
+func TestWireNATDashboardCredentialGate(t *testing.T) {
+	if rpc.NATDashboardCredentialGateWired() {
+		t.Fatal("NAT dashboard credential gate already wired before the test")
+	}
+
+	wireNATDashboardCredentialGate()
+
+	if !rpc.NATDashboardCredentialGateWired() {
+		t.Fatal("wireNATDashboardCredentialGate left the NAT dashboard credential gate unwired")
+	}
+	// Leave the process in the wired state main() establishes.
+	t.Cleanup(wireNATDashboardCredentialGate)
+}
diff --git a/cmd/dashboard/main.go b/cmd/dashboard/main.go
index 69b905db..4b64c441 100644
--- a/cmd/dashboard/main.go
+++ b/cmd/dashboard/main.go
@@ -169,6 +169,7 @@ func main() {
 	grpcHandler := rpc.ServeRPC()
 	httpHandler := controller.ServeWeb(frontendDist)
 	controller.InitUpgrader()
+	wireNATDashboardCredentialGate()
 
 	muxHandler := newHTTPandGRPCMux(httpHandler, grpcHandler)
 	muxServerHTTP := &http.Server{
@@ -228,6 +229,18 @@ func main() {
 	close(errChan)
 }
 
+// wireNATDashboardCredentialGate connects the NAT ingress to the real
+// dashboard-credential classifiers. The NAT ingress strips dashboard-issued
+// credentials (panel JWT / panel PAT) from every channel the panel's own
+// TokenLookup accepts — the Authorization header, the ?token= query parameter
+// and the nz-jwt cookie — before tunneling a request to the agent, and
+// forwards foreign values untouched. ServeWeb built the JWT parser the
+// classifiers reuse, so the gate is wired right after it and before any
+// listener starts serving.
+func wireNATDashboardCredentialGate() {
+	rpc.SetNATDashboardCredentialGate(controller.IsDashboardCredential, controller.IsDashboardCredentialValue)
+}
+
 func newHTTPandGRPCMux(httpHandler http.Handler, grpcHandler http.Handler) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		natConfig := singleton.NATShared.GetNATConfigByDomain(r.Host)
diff --git a/cmd/dashboard/rpc/nat.go b/cmd/dashboard/rpc/nat.go
index d5b3acb6..7b8be72b 100644
--- a/cmd/dashboard/rpc/nat.go
+++ b/cmd/dashboard/rpc/nat.go
@@ -80,7 +80,15 @@ func ServeNAT(w http.ResponseWriter, r *http.Request, natConfig *model.NAT) {
 		return
 	}
 
-	// Authorization authenticates Dashboard access before NAT ingress; it must not become an origin credential for the configured NAT backend.
+	// Credential invariant at NAT ingress: credentials issued by this
+	// dashboard — the panel-signed JWT (verified by signature only, expiry
+	// deliberately ignored) and the panel API token — must never become origin
+	// credentials for the configured NAT backend. prepareNATCapability has
+	// already stripped them from every channel the panel's own TokenLookup
+	// accepts (Authorization header, ?token= query parameter, nz-jwt cookie);
+	// whatever remains on those channels is either absent or a foreign
+	// credential, which is forwarded untouched because the NAT backend may
+	// authenticate with credentials of its own.
 	wWrapped, err := utils.NewRequestWrapper(r, w)
 	if err != nil {
 		return
diff --git a/cmd/dashboard/rpc/nat_capability_agentcompat.go b/cmd/dashboard/rpc/nat_capability_agentcompat.go
index d346ae77..16fdf503 100644
--- a/cmd/dashboard/rpc/nat_capability_agentcompat.go
+++ b/cmd/dashboard/rpc/nat_capability_agentcompat.go
@@ -22,16 +22,26 @@ type natCapabilityLease struct {
 func prepareNATCapability(request *http.Request, natConfig *model.NAT) (natCapabilityLease, error) {
 	values := request.Header.Values(agentcompatcontract.IOStreamCapabilityHeader)
 	if len(values) == 0 {
-		request.Header.Del("Authorization")
+		// No capability header: legacy NAT path. Strip dashboard-issued
+		// credentials (panel JWT or panel PAT) from the Authorization header,
+		// the ?token= query parameter and the nz-jwt cookie so they never
+		// become origin credentials; foreign values are ordinary request data.
+		stripDashboardCredentials(request)
 		return natCapabilityLease{}, nil
 	}
 	request.Header.Del(agentcompatcontract.IOStreamCapabilityHeader)
 	if len(values) != 1 || values[0] == "" {
-		request.Header.Del("Authorization")
+		// Invalid capability: nothing is forwarded, but dashboard-issued
+		// credentials still must not survive into errors or task data.
+		stripDashboardCredentials(request)
 		return natCapabilityLease{}, errors.New("invalid NAT capability")
 	}
 	access, handle, err := serviceRPC.NezhaHandlerSingleton.ConsumeAgentCompatNATCapabilityForProfile(values[0], natConfig.ServerID, natConfig.ID)
-	request.Header.Del("Authorization")
+	// From here the request bytes may reach the agent (active lease) or the
+	// request ends in a 503; either way dashboard-issued credentials are
+	// stripped from every TokenLookup channel, foreign ones are forwarded
+	// untouched.
+	stripDashboardCredentials(request)
 	if err != nil {
 		return natCapabilityLease{}, errors.New("invalid NAT capability")
 	}
diff --git a/cmd/dashboard/rpc/nat_capability_agentcompat_test.go b/cmd/dashboard/rpc/nat_capability_agentcompat_test.go
index 94910c40..2bfae4a8 100644
--- a/cmd/dashboard/rpc/nat_capability_agentcompat_test.go
+++ b/cmd/dashboard/rpc/nat_capability_agentcompat_test.go
@@ -4,8 +4,10 @@ package rpc
 
 import (
 	"bytes"
+	"context"
 	"log"
 	"net/http"
+	"net/url"
 	"strings"
 	"testing"
 
@@ -59,7 +61,193 @@ func TestPrepareNATCapabilityRejectsDuplicateHeaderAfterRemovingAllValues(t *tes
 	}
 }
 
+func TestPrepareNATCapabilityAgentCompatStripsDashboardCredentials(t *testing.T) {
+	// Given — legacy path without a capability header, then the invalid
+	// capability path: both must drop dashboard-issued credentials from the
+	// Authorization header, the ?token= query parameter and the nz-jwt cookie.
+	installNATCredentialTestGate(t)
+	for name, credential := range map[string]string{
+		"dashboard jwt":         natTestDashboardJWTValue,
+		"expired dashboard jwt": natTestDashboardExpiredJWTValue,
+		"dashboard api token":   natTestDashboardPATValue,
+	} {
+		t.Run(name+"/legacy path", func(t *testing.T) {
+			request := &http.Request{
+				Header: make(http.Header),
+				URL:    &url.URL{Path: "/nat", RawQuery: "keep=1&token=" + credential},
+			}
+			request.Header.Set("Authorization", "Bearer "+credential)
+			request.Header.Set("Cookie", "sid=abc; nz-jwt="+credential)
+
+			lease, err := prepareNATCapability(request, &model.NAT{Common: model.Common{ID: 91}, ServerID: 81})
+
+			if err != nil {
+				t.Fatalf("legacy NAT path returned error: %v", err)
+			}
+			if lease.active {
+				t.Fatal("legacy NAT path unexpectedly activated")
+			}
+			if got := request.Header.Get("Authorization"); got != "" {
+				t.Fatalf("legacy NAT path retained dashboard credential in Authorization %q", got)
+			}
+			if got := request.URL.RawQuery; got != "keep=1" {
+				t.Fatalf("legacy NAT path retained dashboard credential in query %q", got)
+			}
+			if got := request.Header.Get("Cookie"); got != "sid=abc" {
+				t.Fatalf("legacy NAT path retained dashboard credential in cookie %q", got)
+			}
+		})
+		t.Run(name+"/invalid capability path", func(t *testing.T) {
+			request := &http.Request{
+				Header: make(http.Header),
+				URL:    &url.URL{Path: "/nat", RawQuery: "keep=1&token=" + credential},
+			}
+			request.Header.Set(agentcompatcontract.IOStreamCapabilityHeader, "malformed")
+			request.Header.Set("Authorization", "Bearer "+credential)
+			request.Header.Set("Cookie", "sid=abc; nz-jwt="+credential)
+
+			lease, err := prepareNATCapability(request, &model.NAT{Common: model.Common{ID: 91}, ServerID: 81})
+
+			if err == nil {
+				t.Fatal("malformed capability unexpectedly accepted")
+			}
+			if lease.active {
+				t.Fatal("malformed capability unexpectedly activated")
+			}
+			if got := request.Header.Get("Authorization"); got != "" {
+				t.Fatalf("invalid capability path retained dashboard credential in Authorization %q", got)
+			}
+			if got := request.URL.RawQuery; got != "keep=1" {
+				t.Fatalf("invalid capability path retained dashboard credential in query %q", got)
+			}
+			if got := request.Header.Get("Cookie"); got != "sid=abc" {
+				t.Fatalf("invalid capability path retained dashboard credential in cookie %q", got)
+			}
+		})
+	}
+}
+
+func TestPrepareNATCapabilityAgentCompatStripsDashboardCredentialAfterConsumingCapability(t *testing.T) {
+	// Given — a well-formed capability that consumes successfully: the request
+	// is about to be tunneled, so the dashboard credential must be gone.
+	installNATCredentialTestGate(t)
+	handler := serviceRPC.NewNezhaHandler()
+	original := serviceRPC.NezhaHandlerSingleton
+	serviceRPC.NezhaHandlerSingleton = handler
+	t.Cleanup(func() { serviceRPC.NezhaHandlerSingleton = original })
+
+	capability, err := handler.RegisterAgentCompatIOStreamCapability(context.Background(), serviceRPC.AgentCompatCapabilityRegistration{
+		Owner:               serviceRPC.AgentCompatCapabilityOwner{PATID: 1, UserID: 2},
+		Purpose:             serviceRPC.AgentCompatCapabilityNAT,
+		TargetServerID:      81,
+		ResourceID:          91,
+		ServerAccessAllowed: true,
+	})
+	if err != nil {
+		t.Fatalf("register capability: %v", err)
+	}
+	request := &http.Request{
+		Header: make(http.Header),
+		URL:    &url.URL{Path: "/nat", RawQuery: "keep=1&token=" + natTestDashboardJWTValue},
+	}
+	request.Header.Set(agentcompatcontract.IOStreamCapabilityHeader, capability.String())
+	request.Header.Set("Authorization", natTestDashboardJWT)
+	request.Header.Set("Cookie", "sid=abc; nz-jwt="+natTestDashboardJWTValue)
+
+	// When
+	lease, err := prepareNATCapability(request, &model.NAT{Common: model.Common{ID: 91}, ServerID: 81})
+
+	// Then
+	if err != nil {
+		t.Fatalf("valid NAT capability rejected: %v", err)
+	}
+	if !lease.active {
+		t.Fatal("valid NAT capability did not activate")
+	}
+	if got := request.Header.Get("Authorization"); got != "" {
+		t.Fatalf("dashboard credential retained in Authorization after capability consumption: %q", got)
+	}
+	if got := request.URL.RawQuery; got != "keep=1" {
+		t.Fatalf("dashboard credential retained in query after capability consumption: %q", got)
+	}
+	if got := request.Header.Get("Cookie"); got != "sid=abc" {
+		t.Fatalf("dashboard credential retained in cookie after capability consumption: %q", got)
+	}
+}
+
+func TestPrepareNATCapabilityAgentCompatKeepsForeignAndMissingAuthorization(t *testing.T) {
+	// Given — legacy path: foreign credentials are ordinary request data and
+	// an absent header must stay untouched.
+	installNATCredentialTestGate(t)
+	for name, values := range map[string][]string{
+		"foreign jwt":    {natTestForeignJWT},
+		"foreign random": {natTestForeignRandom},
+		"empty value":    {""},
+		"missing header": nil,
+	} {
+		t.Run(name, func(t *testing.T) {
+			request := &http.Request{Header: make(http.Header)}
+			for _, value := range values {
+				request.Header.Set("Authorization", value)
+			}
+
+			lease, err := prepareNATCapability(request, &model.NAT{Common: model.Common{ID: 91}, ServerID: 81})
+
+			if err != nil {
+				t.Fatalf("legacy NAT path returned error: %v", err)
+			}
+			if lease.active {
+				t.Fatal("legacy NAT path unexpectedly activated")
+			}
+			got := request.Header.Values("Authorization")
+			if len(got) != len(values) {
+				t.Fatalf("legacy NAT path changed Authorization to %q, want %q", got, values)
+			}
+			for i := range values {
+				if got[i] != values[i] {
+					t.Fatalf("legacy NAT path changed Authorization to %q, want %q", got, values)
+				}
+			}
+		})
+	}
+}
+
+func TestPrepareNATCapabilityAgentCompatKeepsForeignAndMissingQueryAndCookie(t *testing.T) {
+	// Given — legacy path: foreign query tokens and cookies are ordinary
+	// request data, and absent channels must stay untouched.
+	installNATCredentialTestGate(t)
+	for name, tc := range map[string]struct{ rawQuery, cookie string }{
+		"foreign values":  {"keep=1&token=" + natTestForeignJWTValue + "&a=%2Fx", "sid=abc; nz-jwt=" + natTestForeignJWTValue},
+		"empty values":    {"keep=1&token=", "nz-jwt="},
+		"missing channel": {"keep=1", "sid=abc"},
+	} {
+		t.Run(name, func(t *testing.T) {
+			request := &http.Request{
+				Header: make(http.Header),
+				URL:    &url.URL{Path: "/nat", RawQuery: tc.rawQuery},
+			}
+			request.Header.Set("Cookie", tc.cookie)
+
+			lease, err := prepareNATCapability(request, &model.NAT{Common: model.Common{ID: 91}, ServerID: 81})
+
+			if err != nil {
+				t.Fatalf("legacy NAT path returned error: %v", err)
+			}
+			if lease.active {
+				t.Fatal("legacy NAT path unexpectedly activated")
+			}
+			if got := request.URL.RawQuery; got != tc.rawQuery {
+				t.Fatalf("legacy NAT path changed query to %q, want %q", got, tc.rawQuery)
+			}
+			if got := request.Header.Get("Cookie"); got != tc.cookie {
+				t.Fatalf("legacy NAT path changed cookie to %q, want %q", got, tc.cookie)
+			}
+		})
+	}
+}
+
 func TestServeNATAgentCompatSensitiveHeadersStayOutOfErrorsAndLogs(t *testing.T) {
+	installNATCredentialTestGate(t)
 	request := &http.Request{Header: make(http.Header)}
 	request.Header.Set(agentcompatcontract.IOStreamCapabilityHeader, "capability-secret")
 	request.Header.Set("Authorization", "Bearer deterministic-secret")
diff --git a/cmd/dashboard/rpc/nat_capability_default.go b/cmd/dashboard/rpc/nat_capability_default.go
index 8773477b..b0480ce6 100644
--- a/cmd/dashboard/rpc/nat_capability_default.go
+++ b/cmd/dashboard/rpc/nat_capability_default.go
@@ -18,7 +18,12 @@ type natCapabilityLease struct {
 }
 
 func prepareNATCapability(request *http.Request, _ *model.NAT) (natCapabilityLease, error) {
-	request.Header.Del("Authorization")
+	// The default build has no capability protocol: every request takes the
+	// legacy NAT path, so any dashboard-issued credential (panel JWT or panel
+	// PAT) carried by the Authorization header, the ?token= query parameter or
+	// the nz-jwt cookie is stripped before the request is tunneled to the
+	// agent. Foreign values are ordinary request data and stay put.
+	stripDashboardCredentials(request)
 	return natCapabilityLease{}, nil
 }
 
diff --git a/cmd/dashboard/rpc/nat_capability_default_flow_test.go b/cmd/dashboard/rpc/nat_capability_default_flow_test.go
index c3698afa..30c7d71b 100644
--- a/cmd/dashboard/rpc/nat_capability_default_flow_test.go
+++ b/cmd/dashboard/rpc/nat_capability_default_flow_test.go
@@ -19,6 +19,7 @@ import (
 
 func TestServeNATDefaultForwardsCapabilityHeaderAsOrdinaryData(t *testing.T) {
 	fixture := newServeNATFixture(t)
+	installNATCredentialTestGate(t)
 	connection := newServeNATConn()
 	agent := &serveNATAgent{readErr: io.EOF, writeDone: make(chan struct{})}
 	request := &http.Request{
@@ -28,7 +29,7 @@ func TestServeNATDefaultForwardsCapabilityHeaderAsOrdinaryData(t *testing.T) {
 		Body:   &serveNATBody{},
 	}
 	request.Header.Set(agentcompatcontract.IOStreamCapabilityHeader, "ordinary-data")
-	request.Header.Set("Authorization", "Bearer deterministic-secret")
+	request.Header.Set("Authorization", natTestForeignRandom)
 	fixture.taskStream.onSend = func(task *proto.Task) error {
 		var nat model.TaskNAT
 		if err := json.Unmarshal([]byte(task.Data), &nat); err != nil {
@@ -58,7 +59,50 @@ func TestServeNATDefaultForwardsCapabilityHeaderAsOrdinaryData(t *testing.T) {
 	if !strings.Contains(forwarded, strings.ToLower(agentcompatcontract.IOStreamCapabilityHeader)+": ordinary-data") {
 		t.Fatal("default NAT flow did not forward capability header as ordinary request data")
 	}
-	if strings.Contains(forwarded, "Authorization:") || strings.Contains(forwarded, "deterministic-secret") {
-		t.Fatal("default NAT flow forwarded Authorization credentials")
+	if !strings.Contains(forwarded, strings.ToLower("Authorization: "+natTestForeignRandom)) {
+		t.Fatal("default NAT flow stripped a foreign credential that does not belong to the dashboard")
+	}
+}
+
+func TestServeNATDefaultDoesNotForwardDashboardCredentials(t *testing.T) {
+	fixture := newServeNATFixture(t)
+	installNATCredentialTestGate(t)
+	connection := newServeNATConn()
+	agent := &serveNATAgent{readErr: io.EOF, writeDone: make(chan struct{})}
+	request := &http.Request{
+		Method: http.MethodPost,
+		URL:    &url.URL{Scheme: "http", Host: "example.test", Path: "/nat"},
+		Header: make(http.Header),
+		Body:   &serveNATBody{},
+	}
+	request.Header.Set("Authorization", natTestDashboardJWT)
+	fixture.taskStream.onSend = func(task *proto.Task) error {
+		var nat model.TaskNAT
+		if err := json.Unmarshal([]byte(task.Data), &nat); err != nil {
+			return err
+		}
+		return fixture.handler.AgentConnected(nat.StreamID, agent)
+	}
+	done := make(chan struct{})
+	deadline, cancel := context.WithTimeout(context.Background(), time.Second)
+	defer cancel()
+	go func() {
+		ServeNAT(&serveNATResponseWriter{conn: connection}, request, &model.NAT{ServerID: fixture.server.ID, Host: "target.example"})
+		close(done)
+	}()
+	select {
+	case <-agent.writeDone:
+	case <-deadline.Done():
+		t.Fatal("agent did not receive ordinary NAT request")
+	}
+	_ = connection.Close()
+	select {
+	case <-done:
+	case <-deadline.Done():
+		t.Fatal("ServeNAT did not finish")
+	}
+	forwarded := strings.ToLower(string(agent.writtenBytes()))
+	if strings.Contains(forwarded, "authorization:") || strings.Contains(forwarded, "dashboard-signed-jwt") {
+		t.Fatal("default NAT flow forwarded dashboard credentials")
 	}
 }
diff --git a/cmd/dashboard/rpc/nat_capability_default_test.go b/cmd/dashboard/rpc/nat_capability_default_test.go
index 7ff5e686..40827939 100644
--- a/cmd/dashboard/rpc/nat_capability_default_test.go
+++ b/cmd/dashboard/rpc/nat_capability_default_test.go
@@ -4,6 +4,7 @@ package rpc
 
 import (
 	"net/http"
+	"net/url"
 	"testing"
 
 	"github.com/nezhahq/nezha/model"
@@ -12,9 +13,10 @@ import (
 
 func TestPrepareNATCapabilityDefaultPreservesHeaderAsOrdinaryRequestData(t *testing.T) {
 	// Given
+	installNATCredentialTestGate(t)
 	request := &http.Request{Header: make(http.Header)}
 	request.Header.Set(agentcompatcontract.IOStreamCapabilityHeader, "ordinary-data")
-	request.Header.Set("Authorization", "Bearer deterministic-secret")
+	request.Header.Set("Authorization", natTestForeignRandom)
 
 	// When
 	lease, err := prepareNATCapability(request, &model.NAT{Common: model.Common{ID: 91}, ServerID: 81})
@@ -29,7 +31,119 @@ func TestPrepareNATCapabilityDefaultPreservesHeaderAsOrdinaryRequestData(t *test
 	if got := request.Header.Get(agentcompatcontract.IOStreamCapabilityHeader); got != "ordinary-data" {
 		t.Fatalf("default NAT capability hook changed header to %q", got)
 	}
-	if got := request.Header.Get("Authorization"); got != "" {
-		t.Fatalf("default NAT capability hook retained Authorization %q", got)
+	if got := request.Header.Get("Authorization"); got != natTestForeignRandom {
+		t.Fatalf("default NAT capability hook changed foreign Authorization to %q", got)
+	}
+}
+
+func TestPrepareNATCapabilityDefaultStripsDashboardCredentials(t *testing.T) {
+	// Given
+	installNATCredentialTestGate(t)
+	for name, credential := range map[string]string{
+		"dashboard jwt":         natTestDashboardJWTValue,
+		"expired dashboard jwt": natTestDashboardExpiredJWTValue,
+		"dashboard api token":   natTestDashboardPATValue,
+	} {
+		t.Run(name, func(t *testing.T) {
+			request := &http.Request{
+				Header: make(http.Header),
+				URL:    &url.URL{Path: "/nat", RawQuery: "keep=1&token=" + credential},
+			}
+			request.Header.Set("Authorization", "Bearer "+credential)
+			request.Header.Set("Cookie", "sid=abc; nz-jwt="+credential)
+
+			// When
+			lease, err := prepareNATCapability(request, &model.NAT{Common: model.Common{ID: 91}, ServerID: 81})
+
+			// Then
+			if err != nil {
+				t.Fatalf("default NAT capability hook returned error: %v", err)
+			}
+			if lease.active {
+				t.Fatal("default NAT capability hook unexpectedly activated")
+			}
+			if got := request.Header.Get("Authorization"); got != "" {
+				t.Fatalf("default NAT capability hook retained dashboard credential in Authorization %q", got)
+			}
+			if got := request.URL.RawQuery; got != "keep=1" {
+				t.Fatalf("default NAT capability hook retained dashboard credential in query %q", got)
+			}
+			if got := request.Header.Get("Cookie"); got != "sid=abc" {
+				t.Fatalf("default NAT capability hook retained dashboard credential in cookie %q", got)
+			}
+		})
+	}
+}
+
+func TestPrepareNATCapabilityDefaultKeepsForeignAndMissingAuthorization(t *testing.T) {
+	// Given
+	installNATCredentialTestGate(t)
+	for name, values := range map[string][]string{
+		"foreign jwt":    {natTestForeignJWT},
+		"foreign random": {natTestForeignRandom},
+		"empty value":    {""},
+		"missing header": nil,
+	} {
+		t.Run(name, func(t *testing.T) {
+			request := &http.Request{Header: make(http.Header)}
+			for _, value := range values {
+				request.Header.Set("Authorization", value)
+			}
+
+			// When
+			lease, err := prepareNATCapability(request, &model.NAT{Common: model.Common{ID: 91}, ServerID: 81})
+
+			// Then
+			if err != nil {
+				t.Fatalf("default NAT capability hook returned error: %v", err)
+			}
+			if lease.active {
+				t.Fatal("default NAT capability hook unexpectedly activated")
+			}
+			got := request.Header.Values("Authorization")
+			if len(got) != len(values) {
+				t.Fatalf("default NAT capability hook changed Authorization to %q, want %q", got, values)
+			}
+			for i := range values {
+				if got[i] != values[i] {
+					t.Fatalf("default NAT capability hook changed Authorization to %q, want %q", got, values)
+				}
+			}
+		})
+	}
+}
+
+func TestPrepareNATCapabilityDefaultKeepsForeignAndMissingQueryAndCookie(t *testing.T) {
+	// Given
+	installNATCredentialTestGate(t)
+	for name, tc := range map[string]struct{ rawQuery, cookie string }{
+		"foreign values":  {"keep=1&token=" + natTestForeignJWTValue + "&a=%2Fx", "sid=abc; nz-jwt=" + natTestForeignJWTValue},
+		"empty values":    {"keep=1&token=", "nz-jwt="},
+		"missing channel": {"keep=1", "sid=abc"},
+	} {
+		t.Run(name, func(t *testing.T) {
+			request := &http.Request{
+				Header: make(http.Header),
+				URL:    &url.URL{Path: "/nat", RawQuery: tc.rawQuery},
+			}
+			request.Header.Set("Cookie", tc.cookie)
+
+			// When
+			lease, err := prepareNATCapability(request, &model.NAT{Common: model.Common{ID: 91}, ServerID: 81})
+
+			// Then
+			if err != nil {
+				t.Fatalf("default NAT capability hook returned error: %v", err)
+			}
+			if lease.active {
+				t.Fatal("default NAT capability hook unexpectedly activated")
+			}
+			if got := request.URL.RawQuery; got != tc.rawQuery {
+				t.Fatalf("default NAT capability hook changed query to %q, want %q", got, tc.rawQuery)
+			}
+			if got := request.Header.Get("Cookie"); got != tc.cookie {
+				t.Fatalf("default NAT capability hook changed cookie to %q, want %q", got, tc.cookie)
+			}
+		})
 	}
 }
diff --git a/cmd/dashboard/rpc/nat_capability_flow_agentcompat_test.go b/cmd/dashboard/rpc/nat_capability_flow_agentcompat_test.go
index 2ed5a003..0bfe381a 100644
--- a/cmd/dashboard/rpc/nat_capability_flow_agentcompat_test.go
+++ b/cmd/dashboard/rpc/nat_capability_flow_agentcompat_test.go
@@ -23,6 +23,7 @@ import (
 
 func TestServeNATAgentCompatPublishesExactStreamAfterRequestTransfer(t *testing.T) {
 	fixture := newServeNATFixture(t)
+	installNATCredentialTestGate(t)
 	capability, err := fixture.handler.RegisterAgentCompatIOStreamCapability(context.Background(), serviceRPC.AgentCompatCapabilityRegistration{
 		Owner:               serviceRPC.AgentCompatCapabilityOwner{PATID: 1, UserID: 2},
 		Purpose:             serviceRPC.AgentCompatCapabilityNAT,
@@ -44,7 +45,7 @@ func TestServeNATAgentCompatPublishesExactStreamAfterRequestTransfer(t *testing.
 		Body:   io.NopCloser(strings.NewReader("payload")),
 	}
 	request.Header.Set(agentcompatcontract.IOStreamCapabilityHeader, capability.String())
-	request.Header.Set("Authorization", "Bearer deterministic-secret")
+	request.Header.Set("Authorization", natTestForeignJWT)
 	request.Header.Set("X-Ordinary-NAT", "ordinary")
 	fixture.taskStream.onSend = func(task *proto.Task) error {
 		var nat model.TaskNAT
@@ -106,8 +107,62 @@ func TestServeNATAgentCompatPublishesExactStreamAfterRequestTransfer(t *testing.
 		require.Contains(t, forwarded, expected)
 	}
 	require.NotContains(t, forwarded, agentcompatcontract.IOStreamCapabilityHeader)
-	require.NotContains(t, forwarded, "Authorization:")
-	require.NotContains(t, forwarded, "deterministic-secret")
+	// Foreign credentials are ordinary request data for the NAT backend and
+	// must survive the transfer; dashboard-issued values are stripped before
+	// any byte leaves the dashboard.
+	require.Contains(t, forwarded, "Authorization: "+natTestForeignJWT)
+}
+
+func TestServeNATAgentCompatDoesNotForwardDashboardCredentials(t *testing.T) {
+	fixture := newServeNATFixture(t)
+	installNATCredentialTestGate(t)
+	capability, err := fixture.handler.RegisterAgentCompatIOStreamCapability(context.Background(), serviceRPC.AgentCompatCapabilityRegistration{
+		Owner:               serviceRPC.AgentCompatCapabilityOwner{PATID: 1, UserID: 2},
+		Purpose:             serviceRPC.AgentCompatCapabilityNAT,
+		TargetServerID:      fixture.server.ID,
+		ResourceID:          91,
+		ServerAccessAllowed: true,
+	})
+	require.NoError(t, err)
+	connection := newServeNATConn()
+	writer := &serveNATResponseWriter{conn: connection}
+	agent := &serveNATAgent{readErr: io.EOF, writeDone: make(chan struct{})}
+	request := &http.Request{
+		Method: http.MethodPost,
+		URL:    &url.URL{Scheme: "http", Host: "example.test", Path: "/nat"},
+		Header: make(http.Header),
+		Body:   io.NopCloser(strings.NewReader("payload")),
+	}
+	request.Header.Set(agentcompatcontract.IOStreamCapabilityHeader, capability.String())
+	request.Header.Set("Authorization", natTestDashboardJWT)
+	fixture.taskStream.onSend = func(task *proto.Task) error {
+		var nat model.TaskNAT
+		if err := json.Unmarshal([]byte(task.Data), &nat); err != nil {
+			return err
+		}
+		return fixture.handler.AgentConnected(nat.StreamID, agent)
+	}
+	done := make(chan struct{})
+	go func() {
+		ServeNAT(writer, request, &model.NAT{Common: model.Common{ID: 91}, ServerID: fixture.server.ID, Host: "target.example"})
+		close(done)
+	}()
+	select {
+	case <-agent.writeDone:
+	case <-time.After(time.Second):
+		t.Fatal("agent did not receive the transferred NAT request")
+	}
+	require.NoError(t, connection.Close())
+	select {
+	case <-done:
+	case <-time.After(time.Second):
+		t.Fatal("ServeNAT did not complete")
+	}
+	forwarded := strings.ToLower(string(agent.writtenBytes()))
+	require.NotContains(t, forwarded, "authorization:")
+	for _, dashboardCredential := range []string{natTestDashboardJWT, natTestDashboardExpiredJWT, natTestDashboardAPIToken} {
+		require.NotContains(t, forwarded, strings.ToLower(dashboardCredential))
+	}
 }
 
 type orderedNATAgent struct {
diff --git a/cmd/dashboard/rpc/nat_credential.go b/cmd/dashboard/rpc/nat_credential.go
new file mode 100644
index 00000000..a9e82f4a
--- /dev/null
+++ b/cmd/dashboard/rpc/nat_credential.go
@@ -0,0 +1,188 @@
+package rpc
+
+import (
+	"net/http"
+	"net/url"
+	"strings"
+)
+
+// Channel names of the panel's own TokenLookup (controller/jwt.go
+// "header: Authorization, query: token, cookie: nz-jwt"). A dashboard JWT
+// can therefore reach the NAT ingress through the Authorization header, the
+// ?token= query parameter or the nz-jwt cookie, and all three must be
+// classified before the request is tunneled to the agent.
+const (
+	natDashboardJWTCookieName     = "nz-jwt"
+	natDashboardJWTQueryParameter = "token"
+)
+
+var (
+	// natDashboardAuthorizationGate classifies an Authorization header value
+	// (case-sensitive "Bearer " scheme included) as a credential issued by
+	// this dashboard.
+	natDashboardAuthorizationGate func(authz string) bool
+	// natDashboardCredentialValueGate classifies a raw credential value — the
+	// part after the "Bearer " scheme, exactly as the ?token= query parameter
+	// and the nz-jwt cookie carry it — as a credential issued by this
+	// dashboard.
+	natDashboardCredentialValueGate func(value string) bool
+)
+
+// SetNATDashboardCredentialGate wires the dashboard-credential classifiers
+// used by the NAT ingress. main() injects
+// controller.IsDashboardCredential and controller.IsDashboardCredentialValue;
+// the setter keeps the rpc package free of a dependency on the controller
+// package, the same pattern as SetReceiptGateListener and
+// SetMCPKillSwitchObserver. A nil function fails closed: every value on that
+// channel is then treated as dashboard-issued and stripped.
+func SetNATDashboardCredentialGate(authorizationClass func(authz string) bool, valueClass func(value string) bool) {
+	natDashboardAuthorizationGate = authorizationClass
+	natDashboardCredentialValueGate = valueClass
+}
+
+// NATDashboardCredentialGateWired reports whether the dashboard-credential
+// classifiers have been wired. It exists so the main() wiring contract can be
+// pinned by a test.
+func NATDashboardCredentialGateWired() bool {
+	return natDashboardAuthorizationGate != nil && natDashboardCredentialValueGate != nil
+}
+
+// stripDashboardCredentials removes credentials issued by this dashboard from
+// every channel the panel's own TokenLookup accepts: the Authorization
+// header, the ?token= query parameter and the nz-jwt cookie. Such credentials
+// authenticate the dashboard itself and must never become origin credentials
+// for the NAT backend. Foreign values are forwarded untouched: the NAT
+// backend may authenticate with credentials of its own, and this dashboard
+// must not make policy for them.
+func stripDashboardCredentials(request *http.Request) {
+	stripDashboardAuthorizationHeader(request)
+	stripDashboardCredentialQuery(request)
+	stripDashboardCredentialCookie(request)
+}
+
+// stripDashboardAuthorizationHeader removes the Authorization header when it
+// carries a dashboard-issued credential.
+func stripDashboardAuthorizationHeader(request *http.Request) {
+	if natDashboardAuthorizationGate == nil {
+		// Gate not wired (early startup or tests): fail closed and keep the
+		// historical behavior of stripping every Authorization header.
+		request.Header.Del("Authorization")
+		return
+	}
+	// A multi-valued Authorization header is malformed traffic, but any
+	// dashboard-issued value in it must still not survive into the tunnel, so
+	// the whole header is dropped when one is recognized.
+	for _, value := range request.Header.Values("Authorization") {
+		if natDashboardAuthorizationGate(value) {
+			request.Header.Del("Authorization")
+			return
+		}
+	}
+}
+
+// stripDashboardCredentialQuery removes ?token= query parameters whose value
+// is a dashboard-issued credential. Every other element of the query string —
+// including foreign token values — is preserved byte-for-byte, so the
+// forwarded request keeps the exact query the client sent.
+func stripDashboardCredentialQuery(request *http.Request) {
+	if request.URL == nil || request.URL.RawQuery == "" {
+		return
+	}
+	elements := strings.Split(request.URL.RawQuery, "&")
+	kept := elements[:0]
+	changed := false
+	for _, element := range elements {
+		if isDashboardCredentialQueryElement(element) {
+			changed = true
+			continue
+		}
+		kept = append(kept, element)
+	}
+	if changed {
+		request.URL.RawQuery = strings.Join(kept, "&")
+	}
+}
+
+// isDashboardCredentialQueryElement reports whether a raw query element
+// carries a dashboard-issued credential in the panel's token parameter.
+func isDashboardCredentialQueryElement(element string) bool {
+	rawName, rawValue, _ := strings.Cut(element, "=")
+	// The panel reads the parameter by its decoded name (gin-jwt c.Query),
+	// so an escaped key must be decoded before comparing.
+	name, err := url.QueryUnescape(rawName)
+	if err != nil || name != natDashboardJWTQueryParameter {
+		return false
+	}
+	if natDashboardCredentialValueGate == nil {
+		return true // fail closed
+	}
+	// A value that fails to decode is one the panel's own query parsing drops
+	// as well, so it can never be a panel credential.
+	decoded, err := url.QueryUnescape(rawValue)
+	if err != nil {
+		return false
+	}
+	return natDashboardCredentialValueGate(decoded)
+}
+
+// stripDashboardCredentialCookie removes nz-jwt cookies whose value is a
+// dashboard-issued credential. All other cookie pairs — including foreign
+// nz-jwt values — are preserved verbatim.
+func stripDashboardCredentialCookie(request *http.Request) {
+	lines := request.Header.Values("Cookie")
+	if len(lines) == 0 {
+		return
+	}
+	changed := false
+	kept := make([]string, 0, len(lines))
+	for _, line := range lines {
+		nextLine, lineChanged := stripDashboardCredentialCookieLine(line)
+		changed = changed || lineChanged
+		if nextLine != "" {
+			kept = append(kept, nextLine)
+		}
+	}
+	if !changed {
+		return
+	}
+	request.Header.Del("Cookie")
+	for _, line := range kept {
+		request.Header.Add("Cookie", line)
+	}
+}
+
+// stripDashboardCredentialCookieLine rewrites a single Cookie header line,
+// dropping the dashboard-issued nz-jwt pairs. Kept pairs keep their raw form,
+// whitespace included — except that a pair following a dropped one no longer
+// carries the removed pair's share of the "; " separator.
+func stripDashboardCredentialCookieLine(line string) (string, bool) {
+	pairs := strings.Split(line, ";")
+	kept := pairs[:0]
+	droppedBeforeFirstKept := true
+	changed := false
+	for _, pair := range pairs {
+		name, value, _ := strings.Cut(pair, "=")
+		if strings.TrimSpace(name) == natDashboardJWTCookieName &&
+			(natDashboardCredentialValueGate == nil || isDashboardCredentialCookieValue(value)) {
+			changed = true
+			continue
+		}
+		if droppedBeforeFirstKept {
+			pair = strings.TrimLeft(pair, " ")
+		}
+		droppedBeforeFirstKept = false
+		kept = append(kept, pair)
+	}
+	if !changed {
+		return line, false
+	}
+	return strings.Join(kept, ";"), true
+}
+
+// isDashboardCredentialCookieValue classifies a raw cookie value the same way
+// the panel's cookie parsing would hand it to the JWT verifier: surrounding
+// whitespace and quoting are presentation, not part of the credential.
+func isDashboardCredentialCookieValue(rawValue string) bool {
+	value := strings.Trim(strings.TrimSpace(rawValue), `"`)
+	return natDashboardCredentialValueGate(value)
+}
diff --git a/cmd/dashboard/rpc/nat_credential_test.go b/cmd/dashboard/rpc/nat_credential_test.go
new file mode 100644
index 00000000..2f7a2be9
--- /dev/null
+++ b/cmd/dashboard/rpc/nat_credential_test.go
@@ -0,0 +1,153 @@
+package rpc
+
+import (
+	"net/http"
+	"net/url"
+	"testing"
+
+	"github.com/nezhahq/nezha/model"
+)
+
+// Values standing in for the credentials this dashboard issues. The fake
+// gates below mirror the contract of controller.IsDashboardCredential and
+// controller.IsDashboardCredentialValue; the real classification semantics —
+// panel JWTs accepted regardless of expiry, foreign-signed JWTs and random
+// strings rejected — are pinned by the controller package tests
+// (dashboard_credential_test.go) and by the flow test that wires the real
+// classifiers into ServeNAT (dashboard_credential_nat_flow_test.go).
+const (
+	natTestDashboardJWTValue        = "dashboard-signed-jwt"
+	natTestDashboardExpiredJWTValue = "dashboard-signed-expired-jwt"
+	natTestDashboardPATValue        = model.APITokenPrefix + "dashboard-issued-pat"
+	natTestForeignJWTValue          = "foreign-signed-jwt"
+	natTestForeignRandomValue       = "foreign-random-string"
+
+	natTestDashboardJWT        = "Bearer " + natTestDashboardJWTValue
+	natTestDashboardExpiredJWT = "Bearer " + natTestDashboardExpiredJWTValue
+	natTestDashboardAPIToken   = "Bearer " + natTestDashboardPATValue
+	natTestForeignJWT          = "Bearer " + natTestForeignJWTValue
+	natTestForeignRandom       = "Bearer " + natTestForeignRandomValue
+)
+
+// installNATCredentialTestGate wires fake dashboard-credential classifiers
+// for the duration of the test: exactly the dashboard-issued test values above
+// are classified as dashboard credentials on every channel, everything else
+// is foreign.
+func installNATCredentialTestGate(t *testing.T) {
+	t.Helper()
+	originalAuthorization := natDashboardAuthorizationGate
+	originalValue := natDashboardCredentialValueGate
+	natDashboardAuthorizationGate = func(authz string) bool {
+		switch authz {
+		case natTestDashboardJWT, natTestDashboardExpiredJWT, natTestDashboardAPIToken:
+			return true
+		default:
+			return false
+		}
+	}
+	natDashboardCredentialValueGate = func(value string) bool {
+		switch value {
+		case natTestDashboardJWTValue, natTestDashboardExpiredJWTValue, natTestDashboardPATValue:
+			return true
+		default:
+			return false
+		}
+	}
+	t.Cleanup(func() {
+		natDashboardAuthorizationGate = originalAuthorization
+		natDashboardCredentialValueGate = originalValue
+	})
+}
+
+func TestStripDashboardCredentialsQueryChannel(t *testing.T) {
+	// Given
+	installNATCredentialTestGate(t)
+	request := &http.Request{URL: &url.URL{Path: "/nat", RawQuery: "keep=1&token=" + natTestDashboardJWTValue + "&token=" + natTestForeignJWTValue + "&a=%2Fx"}}
+
+	// When
+	stripDashboardCredentials(request)
+
+	// Then
+	if got := request.URL.RawQuery; got != "keep=1&token="+natTestForeignJWTValue+"&a=%2Fx" {
+		t.Fatalf("query channel kept %q, want dashboard token dropped and foreign values byte-preserved", got)
+	}
+}
+
+func TestStripDashboardCredentialsQueryChannelEscapedValue(t *testing.T) {
+	// Given — a dashboard token percent-encoded in the query must still be
+	// recognized, while the escaped foreign element stays verbatim.
+	installNATCredentialTestGate(t)
+	request := &http.Request{URL: &url.URL{Path: "/nat", RawQuery: "token=" + url.QueryEscape(natTestDashboardJWTValue) + "&token=" + url.QueryEscape(natTestForeignJWTValue)}}
+
+	// When
+	stripDashboardCredentials(request)
+
+	// Then
+	if got := request.URL.RawQuery; got != "token="+url.QueryEscape(natTestForeignJWTValue) {
+		t.Fatalf("query channel kept %q, want escaped dashboard token dropped and foreign element verbatim", got)
+	}
+}
+
+func TestStripDashboardCredentialsCookieChannel(t *testing.T) {
+	// Given
+	installNATCredentialTestGate(t)
+	request := &http.Request{Header: make(http.Header)}
+	request.Header.Set("Cookie", "sid=abc; nz-jwt="+natTestDashboardJWTValue+"; nz-jwt="+natTestForeignJWTValue+"; theme=dark")
+
+	// When
+	stripDashboardCredentials(request)
+
+	// Then
+	if got := request.Header.Get("Cookie"); got != "sid=abc; nz-jwt="+natTestForeignJWTValue+"; theme=dark" {
+		t.Fatalf("cookie channel kept %q, want dashboard pair dropped and foreign pairs verbatim", got)
+	}
+}
+
+func TestStripDashboardCredentialsCookieChannelQuotedValue(t *testing.T) {
+	// Given — quoting is presentation the panel's cookie parsing strips before
+	// verifying, so a quoted dashboard token must be recognized.
+	installNATCredentialTestGate(t)
+	request := &http.Request{Header: make(http.Header)}
+	request.Header.Set("Cookie", `nz-jwt="`+natTestDashboardJWTValue+`"; sid=abc`)
+
+	// When
+	stripDashboardCredentials(request)
+
+	// Then
+	if got := request.Header.Get("Cookie"); got != "sid=abc" {
+		t.Fatalf("cookie channel kept %q, want quoted dashboard token dropped", got)
+	}
+}
+
+func TestPrepareNATCapabilityFailsClosedWithoutGate(t *testing.T) {
+	// Given — unwired gates: every value on every channel is treated as
+	// dashboard-issued and stripped, foreign ones included.
+	SetNATDashboardCredentialGate(nil, nil)
+	t.Cleanup(func() { SetNATDashboardCredentialGate(nil, nil) })
+	request := &http.Request{
+		Header: make(http.Header),
+		URL:    &url.URL{Path: "/nat", RawQuery: "keep=1&token=" + natTestForeignJWTValue},
+	}
+	request.Header.Set("Authorization", natTestForeignRandom)
+	request.Header.Set("Cookie", "sid=abc; nz-jwt="+natTestForeignJWTValue)
+
+	// When
+	lease, err := prepareNATCapability(request, &model.NAT{Common: model.Common{ID: 91}, ServerID: 81})
+
+	// Then
+	if err != nil {
+		t.Fatalf("fail-closed NAT capability hook returned error: %v", err)
+	}
+	if lease.active {
+		t.Fatal("fail-closed NAT capability hook unexpectedly activated")
+	}
+	if got := request.Header.Get("Authorization"); got != "" {
+		t.Fatalf("fail-closed hook retained Authorization %q", got)
+	}
+	if got := request.URL.RawQuery; got != "keep=1" {
+		t.Fatalf("fail-closed hook kept query %q, want token parameter stripped", got)
+	}
+	if got := request.Header.Get("Cookie"); got != "sid=abc" {
+		t.Fatalf("fail-closed hook kept cookie %q, want nz-jwt pair stripped", got)
+	}
+}