CVE-2026-88008
CVE-2026-88008 · Traefik: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') and Incorrect Authorization
This page contains facts from public vulnerability sources. Check the original advisory before updating.
Traefik is an open source HTTP reverse proxy and load balancer. From 2.11.26 until 2.11.57 and 3.7.13, Traefik forwards a client-supplied Connection header requesting Upgrade, the Upgrade: h2c token, and HTTP2-Settings to a shared backend. If the backend accepts h2c and returns 101 Switching Protocols, Traefik enters a raw tunnel and no longer applies routers, BasicAuth, ForwardAuth, IPAllowList, RateLimit, access logging, metrics, or tracing to later HTTP/2 requests, allowing an unauthenticated request through an unprotected route to reach protected paths on the same backend. This issue is fixed in 2.11.57 and 3.7.13.
CVSS 7.0 · High · EPSS 0.5% · Public exploit
- Published
- Updated
Stack: web
Affected products and versions
traefik
- Versions
- >= 2.11.26, < 2.11.57: Affected
- >= 3.4.2, < 3.7.13: Affected
No fix published
Original sources
- https://github.com/traefik/traefik/security/advisories/GHSA-w4v4-9rw7-5326
- https://github.com/traefik/traefik/pull/13797
- https://github.com/traefik/traefik/commit/a277e94664ffc1ce9543df552d3bbf48d4d3b8b3
- https://github.com/traefik/traefik/releases/tag/v2.11.57
- https://github.com/traefik/traefik/releases/tag/v3.7.13
- https://nvd.nist.gov/vuln/detail/CVE-2026-88008