CVE-2025-66490
Severity CVSS v4.0:
MEDIUM
Type:
Unavailable / Other
Publication date:
09/12/2025
Last modified:
09/12/2025
Description
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.
Impact
Base Score 4.0
6.90
Severity 4.0
MEDIUM