CVE-2025-66491

Traefik has Inverted TLS Verification Logic in its ingress-nginx Provider

Published: Dec 9, 2025Updated: Jan 2, 2026 Sources: CVE List NVD GHSACWE-295

5.9MEDIUM

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.

No summary for this CVE yet.

CVSS Vector Breakdown

Exploitability

AV:NAttack Vector

Network

AC:HAttack Complexity

High

PR:NPrivileges Required

None

UI:NUser Interaction

None

Scope

S:UScope

Unchanged

Impact

C:HConfidentiality

High

I:NIntegrity

None

A:NAvailability

None

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Weaknesses

CWE-295

Affected Products

traefik

oss-projectaka traefik enterprise

traefikOn-prem

Networking Infrastructure / load-balancer-proxy

package-ecosystem

github.com/traefik/traefik/v3

OSS Libraries

Exploitability

Official Patch Available

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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

1 technique

Collection

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References

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

github.com

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

github.com

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

github.com

and 2 more references View all →

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