CVE-2026-88879: Authentication Bypass by Spoofing

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, XAuthUser and X.Auth.User are treated as three distinct headers by Traefik, while backends that derive variable...

CVE-2026-88011: Authentication Bypass by Spoofing

Traefik is an open source HTTP reverse proxy and load balancer. Prior to 2.11.56, and from 3.0.0 until 3.7.12, a client-supplied dot-form header such as X.Authenticated.User survives ForwardAuth replacement and underscoreHeadersStrategy because Go treats it as distinct from X-Authenticated-User...

PT-2026-89699

Summary There is a medium severity vulnerability in Traefik's handling of request headers whose name aliases another header name. Go canonicalizes header names on dashes only, so X-Auth-User, X Auth User and X.Auth.User are three distinct headers to Traefik, while backends that derive variable...

PT-2026-89472

Name of the Vulnerable Software and Affected Versions Traefik versions 1.x Traefik versions prior to 2.11.56 Traefik versions 3.0.0 through 3.7.11 Description Traefik fails to properly handle request headers that act as aliases for other header names. While Go treats headers like...

PT-2026-89390

Name of the Vulnerable Software and Affected Versions Traefik versions 1.x Traefik versions 2.x through 2.11.55 Traefik versions 3.0.0 through 3.7.11 Description Traefik handles request header canonicalization only on dashes, meaning it treats headers like X-Auth-User, X Auth User, and X.Auth.Use...

CVE-2026-71324

A flaw was found in Traefik. Traefik's HTTP reverse proxy can improperly handle HTTP/2 or HTTP/3 CONNECT requests forwarded to an HTTP/1.1 upstream. If the upstream sends a keep-alive non-2xx response and does not fully drain the body, the desynchronized backend socket is returned to a shared poo...

GO-2026-6202 Traefik: ForwardAuth middleware leaks X-Forwarded-Port spoofing via untrusted X-Forwarded-Proto when trustForwardHeader=false in github.com/traefik/traefik

Traefik: ForwardAuth middleware leaks X-Forwarded-Port spoofing via untrusted X-Forwarded-Proto when trustForwardHeader=false in github.com/traefik/traefik...

GO-2026-6211 Traefik: Incomplete fix for CVE-2026-33433 + CVE-2026-39858 cross-cohort: headerField underscore-variant identity spoofing in BasicAuth / DigestAuth / ForwardAuth in github.com/traefik/traefik

Traefik: Incomplete fix for CVE-2026-33433 + CVE-2026-39858 cross-cohort: headerField underscore-variant identity spoofing in BasicAuth / DigestAuth / ForwardAuth in github.com/traefik/traefik...

PT-2026-80432

Traefik: ForwardAuth middleware leaks X-Forwarded-Port spoofing via untrusted X-Forwarded-Proto when trustForwardHeader=false in github.com/traefik/traefik...

Traefik: Incomplete fix for CVE-2026-33433 + CVE-2026-39858 cross-cohort: headerField underscore-variant identity spoofing in BasicAuth / DigestAuth / ForwardAuth

Summary There is a high severity vulnerability in Traefik's BasicAuth, DigestAuth, and ForwardAuth middlewares. The fix for CVE-2026-33433 stripped canonical-cased spoofed identity headers e.g. X-Auth-User before writing Traefik's own value, but did not account for underscore-variant header names...

EUVD-2026-41937

Traefik: ForwardAuth middleware leaks X-Forwarded-Port spoofing via untrusted X-Forwarded-Proto when trustForwardHeader=false...

GHSA-3Q9R-P662-5J8M Traefik: ForwardAuth middleware leaks X-Forwarded-Port spoofing via untrusted X-Forwarded-Proto when trustForwardHeader=false

Summary There is a medium severity vulnerability in Traefik's ForwardAuth middleware. Even when configured with trustForwardHeader: false, Traefik derives the X-Forwarded-Port header sent to the authentication service from the original incoming request instead of the sanitized forwarded request. ...

CVE-2026-71324

Traefik , an open-source HTTP reverse proxy and load balancer, is vulnerable to cross-user response poisoning in its default proxy when forwarding HTTP/2 or HTTP/3 CONNECT requests to an HTTP/1.1 upstream via a shared net/http.Transport . If the upstream returns a keep-alive non-2xx response with...

CVE-2026-71324: Inconsistent Interpretation of HTTP Requests

Traefik is an open source HTTP reverse proxy and load balancer. Prior to 2.11.53, 3.6.24, and 3.7.9, Traefik's default HTTP reverse proxy forwards a plain HTTP/2 or HTTP/3 CONNECT request and its body to an HTTP/1.1 upstream through a shared net/http.Transport. When the upstream answers the CONNE...

CVE-2026-54764

A flaw was found in Traefik, an HTTP reverse proxy and load balancer. The ForwardAuth middleware, even when configured to not trust forwarded headers, incorrectly uses the original incoming request to determine the X-Forwarded-Port header sent to the authentication service. This allows an...

PT-2026-68796

Name of the Vulnerable Software and Affected Versions Traefik versions prior to 2.11.53 Traefik versions prior to 3.6.24 Traefik versions prior to 3.7.9 Description Traefik's default HTTP reverse proxy forwards HTTP/2 or HTTP/3 CONNECT requests and their bodies to HTTP/1.1 upstreams using a share...

SUSE CVE-2026-54764

Traefik is an HTTP reverse proxy and load balancer. Prior to v2.11.51, v3.6.22, and v3.7.6, Traefik's ForwardAuth middleware, even when configured with trustForwardHeader: false, derives the X-Forwarded-Port header sent to the authentication service from the original incoming request instead of t...

Insufficient Verification of Data Authenticity

Overview Affected versions of this package are vulnerable to Insufficient Verification of Data Authenticity in the ForwardAuth process when trustForwardHeader is set to false. An attacker can bypass port-based authorization checks by injecting a crafted X-Forwarded-Proto header over an unencrypte...

CVE-2026-54763

Traefik is an HTTP reverse proxy and load balancer. Prior to v2.11.51, v3.6.22, and v3.7.6, Traefik's BasicAuth, DigestAuth, and ForwardAuth middlewares strip canonical-cased spoofed identity headers before writing Traefik's own value, but do not account for underscore-variant header names, which...

CVE-2026-54764

Traefik is an HTTP reverse proxy and load balancer. Prior to v2.11.51, v3.6.22, and v3.7.6, Traefik's ForwardAuth middleware, even when configured with trustForwardHeader: false, derives the X-Forwarded-Port header sent to the authentication service from the original incoming request instead of t...