CVE-2026-48020: Traefik

Critical severity, CVSS 10.0. EPSS: 0.8% chance of exploitation in the next 30 days.

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.

Affected products

• Traefik Traefik: before 2.11.48 (fixed in 2.11.48); from 3.0.0, before 3.6.19 (fixed in 3.6.19); from 3.7.0, before 3.7.3 (fixed in 3.7.3)

Published 2026-06-23. Last modified 2026-09-02.