Path Normalization Bypass in Traefik Reverse Proxy and Load Balancer
CVE-2025-66490
What is CVE-2025-66490?
The vulnerability in Traefik's HTTP reverse proxy and load balancer allows requests with URL-encoded restricted characters to bypass path normalization. Specifically, requests using PathPrefix, Path, or PathRegex matchers can inadvertently reach unintended backend services without passing through the necessary security controls. This presents a serious risk, particularly for sensitive endpoints such as admin pages, where security middleware may not be activated. It is crucial for users of Traefik to upgrade to versions 2.11.32 or 3.6.3 to mitigate this risk.
Affected Version(s)
traefik github.com/traefik/traefik/v3 < 3.6.3 < github.com/traefik/traefik/v3 3.6.3
traefik github.com/traefik/traefik/v2 < 2.11.32 < github.com/traefik/traefik/v2 2.11.32
traefik github.com/traefik/traefik <= 1.7.34 <= github.com/traefik/traefik 1.7.34