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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
NVD MITRE
EPSS Score
0.2%
Top 87.2%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
OpenVAS

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

AV:NAC:HPR:NUI:NS:UC:HI:NA:N
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
Go
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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