cvedb.io
CVE-2025-66491
MEDIUM · CVSS 5.9
EPSS exploitation probability: 0%
Published 2025-12-09T01:16:55.720 · Last modified 2026-06-17T09:56:55.693

Summary

Traefik is an HTTP reverse proxy and load balancer. Versions 3.5.0 through 3.6.2 have inverted TLS verification logic in the nginx.ingress.kubernetes.io/proxy-ssl-verify annotation. Setting the annotation to "on" (intending to enable backend TLS certificate verification) actually disables verification, allowing man-in-the-middle attacks against HTTPS backends when operators believe they are protected. This issue is fixed in version 3.6.3.

Affected products

traefik — traefik

Does this affect you?

Add your gear to cvedb and we'll alert you only when traefik ships something exploited.

Check my exposure →

References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.