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CVE-2025-66490

CVE-2025-66490 · Traefik doesn't Prevent Path Normalization Bypass in Router + Middleware Rules

This page contains facts from public vulnerability sources. Check the original advisory before updating.

Traefik is an HTTP reverse proxy and load balancer. For versions prior to 2.11.32 and 2.11.31 through 3.6.2, requests using PathPrefix, Path or PathRegex matchers can bypass path normalization. When Traefik uses path-based routing, requests containing URL-encoded restricted characters (/, \, Null, ;, ?, #) can bypass the middleware chain and reach unintended backends. For example, a request to http://mydomain.example.com/admin%2F could reach service-a without triggering my-security-middleware, bypassing security controls for the /admin/ path. This issue is fixed in versions 2.11.32 and 3.6.3.

CVSS 6.9 · Medium · EPSS 0.4%

Published
Updated

Stack: web

Affected products and versions

  • traefik

    Versions
    • github.com/traefik/traefik/v3 < 3.6.3: Affected
    • github.com/traefik/traefik/v2 < 2.11.32: Affected
    • github.com/traefik/traefik <= 1.7.34: Affected

    No fix published

Original sources

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