VULNERABILITY INTELLIGENCE

CVE-2025-66491

CVSS score5.9 MEDIUM
EPSS probability0.22%
CISA KEVNot currently listed
Published2025-12-09
Last modified2026-10-14
CVSS vectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Description

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.

Weakness classification

  • security-advisories@github.com: CWE-295

Primary references