CVE-2025-66491

MEDIUM EPSS 10.6%
Published Dec 9, 20256mo ago · Modified Jun 17, 20261w ago
5.9 CVSS 3.1
Medium
Find Similar
Published Dec 9, 2025 6mo ago
Last Modified Jun 17, 2026 1w ago

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.

CVSS Details

Base Score
5.9
Exploitability
2.2
Impact
3.6
Vector string
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Attack Vector Network
Attack Complexity High
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality High
Integrity None
Availability None

Threat Intelligence

EPSS Exploit Probability
10.6% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-295

Affected Products 1

VendorProductVersionRange
traefiktraefik*≥3.5.0  –  <3.6.3

References 3

  • github.com https://github.com/traefik/traefik/commit/14a1aedf5704673d875d210d7bacf103a43c77e4
    Patch
  • github.com https://github.com/traefik/traefik/releases/tag/v3.6.3
    Release Notes
  • github.com https://github.com/traefik/traefik/security/advisories/GHSA-7vww-mvcr-x6vj
    PatchVendor Advisory

Remediation

  • github.com https://github.com/traefik/traefik/commit/14a1aedf5704673d875d210d7bacf103a43c77e4
    Patch
  • github.com https://github.com/traefik/traefik/security/advisories/GHSA-7vww-mvcr-x6vj
    PatchVendor Advisory