traefik 3.7.1 : vulnérabilités connues

Traefik before 2.11.58 and 3.7.13 mTLS Bypass via Negated Host Matcher

Traefik before 2.11.58 and 3.7.13 contains an authentication bypass vulnerability that allows unauthenticated clients to skip client-certificate checks because negated Host matchers are counted as served domains. Attackers can reach backends protected by RequireAndVerifyClientCert when a router rule with !Host() creates a TLS options conflict that falls back to the default options.

• Mettez à jour vers 3.7.13

Traefik before 2.11.58 and 3.7.14 TLS Config Bypass via NTLM/Kerberos Round Tripper

Traefik 2.11.0 before 2.11.58 and 3.0.0 before 3.7.14 stores its NTLM/Kerberos backend round tripper in a client-connection slot not keyed by ServersTransport, so one service's TLS client configuration is reused for another service's backend. An unauthenticated client can arm the slot via a backend issuing an NTLM or Negotiate challenge, then reach another service on the same keep-alive connection, bypassing its root CAs, server name, and certificate verification.

• Mettez à jour vers 3.7.14

Traefik before 2.11.58 and 3.7.14 Race Condition in NTLM/Kerberos Round Tripper

Traefik 2.11.x before 2.11.58 and 3.x before 3.7.14 contains a race condition in NTLM and Kerberos (Negotiate) backend authentication, where the per-connection sticky round tripper slot is read and written without synchronization. Remote attackers can send concurrent HTTP/2 or HTTP/3 requests over one connection to orphan backend connections, break connection-bound authentication, or crash Traefik.

• Mettez à jour vers 3.7.14

Traefik v3.7.0 before v3.7.14 mTLS Header Spoofing via Ingress-NGINX HTTP Router

Traefik from v3.7.0 before v3.7.14 contains an authentication bypass vulnerability in its Kubernetes Ingress-NGINX provider that forwards client-supplied Ssl-Client-* headers on the plaintext HTTP router. When ssl-redirect is disabled alongside auth-tls-pass-certificate-to-upstream, unauthenticated attackers can send Ssl-Client-Verify: SUCCESS with a chosen certificate subject and issuer to impersonate mTLS identities.

• Mettez à jour vers 3.7.14

Traefik before 2.11.58 and 3.7.14 Authentication Bypass via Negotiate Connection Pool

Traefik 2.11.0 before 2.11.58 and 3.0.0 before 3.7.14 contains an authentication bypass because a first request preauthenticated with an Authorization: Negotiate token authenticates a socket in the globally shared backend connection pool, which is never isolated. Unauthenticated attackers on separate frontend connections can be assigned that NTLM/Kerberos-bound socket and perform reads or writes with the victim's identity.

• Mettez à jour vers 3.7.14

Traefik v3.7.0 before v3.7.14 Client CA Mix-up via auth-tls-secret Name Collision

Traefik v3.7.0 before v3.7.14 contains an improper authentication vulnerability in the Kubernetes Ingress NGINX provider that merges client CAs when auth-tls-secret names collide after dot-to-dash normalization. Attackers holding certificates from another host's CA can access a host requiring its own client CA, while that host's legitimate clients are refused.

• Mettez à jour vers 3.7.14

Traefik v3.2.0 before v3.7.14 FastProxy NTLM/Negotiate Connection Pool Identity Leak

Traefik from v3.2.0 before v3.7.14 contains an authentication bypass vulnerability in the experimental FastProxy connection pool, which fails to pin NTLM/Negotiate-authenticated backend connections to their frontend connection. Unauthenticated clients can be handed a pooled keep-alive backend connection where a victim completed an NTLM or Negotiate handshake, letting them read victim data and act as that victim.

• Mettez à jour vers 3.7.14

Traefik before v2.11.58 and v3.7.14 SNI Check Bypass via HTTP/2 Scheme

Traefik before v2.11.58 and v3.7.14 contains an authentication bypass vulnerability in its SNI check, which is skipped when request TLS state is nil. Unauthenticated clients can send HTTP/2 requests with the :scheme http pseudo-header over TLS on Go 1.27 builds to reach routers requiring client certificates without presenting one.

• Mettez à jour vers 3.7.14

Traefik before v2.11.56 Identity Spoofing via Header Alias

Traefik is an HTTP reverse proxy and load balancer. In Traefik v1.x, v2.x through v2.11.55, and v3.0.0 through v3.7.11, header names are canonicalized only on dashes, so X-Auth-User, X_Auth_User and X.Auth.User are treated as three distinct headers by Traefik, while backends that derive variable names from header names (CGI, WSGI, PHP, NGINX and others) collapse them into a single variable. A client can therefore smuggle a dot-form alias of a header that Traefik manages past the middleware managing it — for example supplying X.Authenticated.User alongside the canonical X-Authenticated-User written by the ForwardAuth middleware — causing such

Traefik v2.8.2 through v3.6 HTTP/3 Timeout Bypass

Traefik is an HTTP reverse proxy and load balancer. In versions >= v2.8.2 through <= v2.11.55 and >= v3.0.0 through <= v3.7.11, the entryPoints.<name>.transport.respondingTimeouts settings — notably readTimeout, which is enabled by default at 60s — are not applied to the HTTP/3 request path. readTimeout is enforced as a deadline on the underlying TCP connection, which cannot be applied to a QUIC stream, and Traefik's HTTP/3 server is constructed without any timeout. As a result, on entry points with HTTP/3 enabled, an unauthenticated remote client that trickles request body bytes can hold a request open indefinitely and, with it, one upstream

Traefik v3.7.0 Authentication Bypass via from-to-www-redirect

Traefik is a HTTP reverse proxy and load balancer. In versions >= v3.7.0 and <= v3.7.11, the Kubernetes ingress-nginx provider mishandles Ingresses that carry both an authentication annotation and the nginx.ingress.kubernetes.io/from-to-www-redirect annotation. For such Ingresses the provider creates an additional 'sibling' router that matches on the host alone, carries only the RedirectRegex middleware, and still points at the parent router's protected backend service. Because RedirectRegex is not a terminal handler, a request its pattern does not match is forwarded to the backend, and because the redirect pattern only accepts a numeric port

Traefik before v2.11.55 and v3.0.0 through v3.7.10 mTLS Bypass via TLS Option Conflict

Traefik before v2.11.55 and v3.0.0 through v3.7.10 contain a TLS option conflict resolution vulnerability that allows unauthenticated attackers to bypass client-certificate authentication by creating conflicting TLS options on multi-host routers. Attackers can reach protected backends by exploiting shared TLS resolution across multiple hostnames in a single router rule, causing the strict mTLS requirement to fall back to default options for all hosts.

Traefik v3.7 Authentication Bypass via TLS Option Conflict

Traefik versions >= v3.7.0 and <= v3.7.10 contain an authentication bypass in the Kubernetes Ingress NGINX provider. The TLS option generated for an Ingress carrying the nginx.ingress.kubernetes.io/auth-tls-secret annotation was named after the Ingress namespace and name. As a result, two Ingress objects sharing the same host, the same client CA secret, and the same client-authentication mode produced two distinct TLS option names for that host. Traefik treats this as a TLS options conflict and falls back to the entry point's default TLS configuration, which does not request a client certificate, so a route configured with nginx.ingress.kuber

Traefik before v2.11.55 and v3.0.0 through v3.7.10 Authentication Bypass via digestAuth

Traefik versions before v2.11.55 and versions v3.0.0 through v3.7.10 contain an authentication bypass vulnerability in the digestAuth middleware where unknown usernames receive an empty secret instead of rejection. Attackers can compute a valid digest response using the empty secret and arbitrary credentials to bypass authentication on any digestAuth-protected route without a valid username or password.

Traefik v3.7.1 crossProviderNamespaces Bypass via Service Middleware

Traefik versions from v3.7.1 fail to enforce crossProviderNamespaces restrictions on the traefik.ingress.kubernetes.io/service.middlewares Service annotation in the Kubernetes Ingress provider. A namespace-limited tenant excluded from the allowlist can attach an operator-owned middleware to its Service, and if that middleware injects backend credentials, recover them at a controlled backend.

Traefik v3.7.0 Path Traversal via RewriteTarget Authentication Bypass

Traefik versions >= v3.7.0 and <= v3.7.7 contain a path traversal vulnerability in the Kubernetes Ingress NGINX provider's RewriteTarget middleware (generated from the nginx.ingress.kubernetes.io/rewrite-target annotation). When an Ingress path uses a regex that captures attacker-controlled text without requiring a path separator (e.g., path /api(.*) with rewrite target /$1), a crafted request such as /api../admin matches the public router, is rewritten to a dot-segment traversal path (/../admin), and is forwarded without post-replacement normalization validation. A backend that normalizes dot segments resolves the path to a protected endpoin

• Mettez à jour vers 3.7.8

Traefik before 3.6.23 IngressRouteTCP ServersTransport Namespace Bypass

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.

• Mettez à jour vers 3.7.7

Traefik before 3.7.7 Namespace Confusion via HTTPRoute ExtensionRef

Traefik versions 3.7.0 through 3.7.6 contain a namespace confusion vulnerability in the Kubernetes Gateway API provider. When resolving HTTPRoute.spec.rules[].backendRefs[].filters[].extensionRef, Traefik used the backend Service namespace instead of the HTTPRoute namespace. A low-privileged route author holding a ReferenceGrant for a cross-namespace Service could therefore bind a Traefik Middleware from the backend namespace without a separate grant for that middleware, potentially injecting trusted reverse-proxy identity headers into downstream requests. The issue is fixed in version 3.7.7.

• Mettez à jour vers 3.7.7

Traefik before v2.11.52 Authentication Bypass via ReplacePathRegex

Traefik versions <= v2.11.51, >= v3.6.0 <= v3.6.22, and >= v3.7.0 <= v3.7.6 contain an authentication bypass via path traversal in the ReplacePathRegex middleware. When ReplacePathRegex is configured with a regex that captures user-controlled path segments without a mandatory path separator (e.g. regex "^/api(.*)", replacement "/$1"), the middleware forwards the replaced path to the backend without validating that it matches its normalized form. An unauthenticated remote attacker can send a crafted request (e.g. GET /api../admin) that produces an un-normalized path such as /../admin, which a backend that normalizes paths resolves to a protect

• Mettez à jour vers 3.7.7