CVE-2025-66490

Summary

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.

Affected Software

VendorProductVersion RangeStatus
traefiktraefikgithub.com/traefik/traefik/v3 < 3.6.3affected
traefiktraefikgithub.com/traefik/traefik/v2 < 2.11.32affected
traefiktraefikgithub.com/traefik/traefik <= 1.7.34affected

Weaknesses

  • CWE-436: CWE-436: Interpretation Conflict

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: poc
    • Automatable: yes
    • Technical Impact: partial

Additional References

References