CVE-2026-48020

Traefik is an HTTP reverse proxy and load balancer. Prior to 2.11.48, 3.6.19, and 3.7.3, there is a high severity vulnerability in Traefik's StripPrefix middleware that allows an unauthenticated attacker to bypass route-level authentication and authorization. When a public router matches on a PathPrefix rule and applies the StripPrefix middleware, a request path containing .. or its percent-encoded form %2e%2e can match the public route at routing time and then, after the prefix is stripped and the path is normalized, resolve to a path served by a separate, authenticated router. As a result, an attacker can reach protected backend paths — such as admin or internal configuration endpoints — without satisfying the authentication middleware attached to the protected router. This vulnerability is fixed in 2.11.48, 3.6.19, and 3.7.3.

• https://github.com/traefik/traefik/releases/tag/v2.11.48
• https://github.com/traefik/traefik/releases/tag/v3.6.19
• https://github.com/traefik/traefik/releases/tag/v3.7.3
• https://github.com/traefik/traefik/security/advisories/GHSA-xf64-8mw2-4gr2