Traefik: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') and Incorrect Authorization

Summary There is a high-severity request-smuggling vulnerability in Traefik's handling of the HTTP/1.1 Upgrade mechanism. Since Traefik moved to unencrypted HTTP/2 with prior knowledge Go 1.24, a client-initiated Upgrade: h2c request header and its connection-specific HTTP2-Settings header were...

GHSA-V67P-PHPQ-FC8X Traefik entrypoint header-name sanitization bypassed via request trailers

Summary Traefik's entrypoint defenses against spoofed trusted header names — aliasHeadersStrategy / underscoreHeadersStrategy in delete or reject mode, and the default forwardedHeaders stripping of client-supplied X-Forwarded- — scan req.Header only and never req.Trailer. An unauthenticated clien...

Traefik entrypoint header-name sanitization bypassed via request trailers

Summary Traefik's entrypoint defenses against spoofed trusted header names — aliasHeadersStrategy / underscoreHeadersStrategy in delete or reject mode, and the default forwardedHeaders stripping of client-supplied X-Forwarded- — scan req.Header only and never req.Trailer. An unauthenticated clien...

GHSA-QQJF-53CJ-PWVV Traefik HTTP/3 Backend NTLM Connection Reuse

Summary Traefik's HTTP/3 request path did not initialize the connection-scoped backend transport holder that isolates connection-bound NTLM and Negotiate Kerberos authentication on the HTTP/1.1 and HTTP/2 paths. The HTTP/3 entrypoint reuses the HTTPS handler chain and reaches the same backend...

Traefik HTTP/3 Backend NTLM Connection Reuse

Summary Traefik's HTTP/3 request path did not initialize the connection-scoped backend transport holder that isolates connection-bound NTLM and Negotiate Kerberos authentication on the HTTP/1.1 and HTTP/2 paths. The HTTP/3 entrypoint reuses the HTTPS handler chain and reaches the same backend...

GHSA-F52W-8J3H-J724 Traefik: Rootless HTTP/1 request-target routes as "/" but is forwarded verbatim, bypassing path-scoped routing, middleware guards and access logging

Summary Traefik accepts an HTTP/1.x request whose request-target is in rootless / opaque form for example GET http:http://internal-vhost/admin HTTP/1.1. Go parses this into URL.Opaque with an empty URL.Path, so Traefik evaluates all routing, path-sanitization, middleware and access-log decisions...

Traefik: Rootless HTTP/1 request-target routes as "/" but is forwarded verbatim, bypassing path-scoped routing, middleware guards and access logging

Summary Traefik accepts an HTTP/1.x request whose request-target is in rootless / opaque form for example GET http:http://internal-vhost/admin HTTP/1.1. Go parses this into URL.Opaque with an empty URL.Path, so Traefik evaluates all routing, path-sanitization, middleware and access-log decisions...

CVE-2026-88012

creationtimestamp| type| source ---|---|--- 2026-09-10 22:35:12+00:00| published-proof-of-concept| https://github.com/traefik/traefik/security/advisories/GHSA-7ghq-v6jf-g56c...

CVE-2026-88011

creationtimestamp| type| source ---|---|--- 2026-09-10 22:35:10+00:00| published-proof-of-concept| https://github.com/traefik/traefik/security/advisories/GHSA-rf44-j88r-hh8c...

GHSA-RF44-J88R-HH8C Traefik: ForwardAuth identity spoofing via dot-form header alias

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, XAuthUser and X.Auth.User are three distinct headers to Traefik, while backends that derive variable name...

Traefik: ForwardAuth identity spoofing via dot-form header alias

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, XAuthUser and X.Auth.User are three distinct headers to Traefik, while backends that derive variable name...

GHSA-7GHQ-V6JF-G56C Traefik: respondingTimeouts.readTimeout is not applied to HTTP/3, leaving slow-body uploads unbounded

Summary There is a medium severity vulnerability in Traefik's HTTP/3 entry points: the respondingTimeouts settings were not applied to the HTTP/3 request path. readTimeout in particular is on by default at 60s and is documented as bounding the time to read the entire request including its body, b...

Traefik: respondingTimeouts.readTimeout is not applied to HTTP/3, leaving slow-body uploads unbounded

Summary There is a medium severity vulnerability in Traefik's HTTP/3 entry points: the respondingTimeouts settings were not applied to the HTTP/3 request path. readTimeout in particular is on by default at 60s and is documented as bounding the time to read the entire request including its body, b...

CVE-2026-88012

Traefik is an open source HTTP reverse proxy and load balancer. From 2.8.2 until 2.11.56 and 3.7.12, HTTP/3 entrypoints do not apply entryPoints..transport.respondingTimeouts.readTimeout because the timeout is enforced on a TCP connection and the HTTP/3 server has no corresponding QUIC stream...

CVE-2026-88011

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...

CVE-2026-88009

Traefik is an open source HTTP reverse proxy and load balancer. Prior to 2.11.57, and 3.7.13, Traefik accepts a rootless HTTP/1 request target that Go stores in URL.Opaque while leaving URL.Path empty. The rewriteRequestBuilder path evaluates routing, path sanitization, forwardAuth,...

CVE-2026-88012

Traefik , the open-source HTTP reverse proxy and load balancer, has a flaw in how HTTP/3 entrypoints handle respondingTimeouts.readTimeout . The timeout is enforced at the TCP layer, but HTTP/3 operates over QUIC , which has no corresponding stream deadline. This means an unauthenticated attacker...

CVE-2026-88012 Traefik: respondingTimeouts.readTimeout is not applied to HTTP/3, leaving slow-body uploads unbounded

Traefik is an open source HTTP reverse proxy and load balancer. From 2.8.2 until 2.11.56 and 3.7.12, HTTP/3 entrypoints do not apply entryPoints..transport.respondingTimeouts.readTimeout because the timeout is enforced on a TCP connection and the HTTP/3 server has no corresponding QUIC stream...

CVE-2026-88012 Traefik: respondingTimeouts.readTimeout is not applied to HTTP/3, leaving slow-body uploads unbounded

Traefik is an open source HTTP reverse proxy and load balancer. From 2.8.2 until 2.11.56 and 3.7.12, HTTP/3 entrypoints do not apply entryPoints..transport.respondingTimeouts.readTimeout because the timeout is enforced on a TCP connection and the HTTP/3 server has no corresponding QUIC stream...

CVE-2026-88012

Traefik is an open source HTTP reverse proxy and load balancer. From 2.8.2 until 2.11.56 and 3.7.12, HTTP/3 entrypoints do not apply entryPoints..transport.respondingTimeouts.readTimeout because the timeout is enforced on a TCP connection and the HTTP/3 server has no corresponding QUIC stream...