CVE-2025-66491

medium

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.

References

https://github.com/traefik/traefik/security/advisories/GHSA-7vww-mvcr-x6vj

https://github.com/traefik/traefik/releases/tag/v3.6.3

https://github.com/traefik/traefik/commit/14a1aedf5704673d875d210d7bacf103a43c77e4

Details

Source: Mitre, NVD

Published: 2025-12-09

Updated: 2025-12-09

Risk Information

CVSS v2

Base Score: 5.4

Vector: CVSS2#AV:N/AC:H/Au:N/C:C/I:N/A:N

Severity: Medium

CVSS v3

Base Score: 5.9

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Severity: Medium

EPSS

EPSS: 0.00006