CVE-2025-66491
Dec. 9, 2025, 6:37 p.m.
5.9
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.
Product(s) Impacted
| Vendor | Product | Versions |
|---|---|---|
| Traefik |
|
|
Weaknesses
Common security weaknesses mapped to this vulnerability.
CWE-295
Improper Certificate Validation
The product does not validate, or incorrectly validates, a certificate.
*CPE(s)
Affected systems and software identified for this CVE.
| Type | Vendor | Product | Version | Update | Edition | Language | Software Edition | Target Software | Target Hardware | Other Information |
|---|---|---|---|---|---|---|---|---|---|---|
| a | traefik | traefik | 3.5.0-3.6.2 | / | / | / | / | / | / | / |
| a | traefik | traefik | 3.6.3 | / | / | / | / | / | / | / |
Tags
CVSS Score
CVSS Data - 3.1
- Attack Vector: NETWORK
- Attack Complexity: HIGH
- Privileges Required: NONE
- Scope: UNCHANGED
- Confidentiality Impact: HIGH
- Integrity Impact: NONE
- Availability Impact: NONE
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Timeline
Published: Dec. 9, 2025, 1:16 a.m.
Last Modified: Dec. 9, 2025, 6:37 p.m.
Last Modified: Dec. 9, 2025, 6:37 p.m.
Status : Awaiting Analysis
CVE has been recently published to the CVE List and has been received by the NVD.
More infoSource
security-advisories@github.com
*Disclaimer: Some vulnerabilities do not have an associated CPE. To enhance the data, we use AI to infer CPEs based on CVE details. This is an automated process and might not always be accurate.