Traefik up to 3.6.2 certificate validation

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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4.7$0-$5k0.00

Summaryinfo

A vulnerability has been found in Traefik up to 3.6.2 and classified as critical. This vulnerability affects unknown code. Performing a manipulation results in certificate validation. This vulnerability was named CVE-2025-66491. The attack may be initiated remotely. There is no available exploit. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as problematic has been found in Traefik up to 3.6.2. This affects an unknown part. The manipulation with an unknown input leads to a certificate validation vulnerability. CWE is classifying the issue as CWE-295. The product does not validate, or incorrectly validates, a certificate. This is going to have an impact on integrity. The summary by CVE is:

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.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2025-66491 since 12/02/2025. The exploitability is told to be difficult. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Neither technical details nor an exploit are publicly available. MITRE ATT&CK project uses the attack technique T1587.003 for this issue.

Upgrading to version 3.6.3 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch 14a1aedf5704673d875d210d7bacf103a43c77e4 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.8
VulDB Meta Temp Score: 4.7

VulDB Base Score: 3.7
VulDB Temp Score: 3.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 5.9
CNA Vector (GitHub_M): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Certificate validation
CWE: CWE-295 / CWE-287
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Traefik 3.6.3
Patch: 14a1aedf5704673d875d210d7bacf103a43c77e4

Timelineinfo

12/02/2025 CVE reserved
12/09/2025 +7 days Advisory disclosed
12/09/2025 +0 days VulDB entry created
12/09/2025 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: GHSA-7vww-mvcr-x6vj
Status: Confirmed

CVE: CVE-2025-66491 (🔒)
GCVE (CVE): GCVE-0-2025-66491
GCVE (VulDB): GCVE-100-334953

Entryinfo

Created: 12/09/2025 07:56
Changes: 12/09/2025 07:56 (66)
Complete: 🔍
Cache ID: 216:949:103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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