CVE-2025-66491

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Source
https://cve.org/CVERecord?id=CVE-2025-66491
Import Source
https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-66491.json
JSON Data
https://api.test.osv.dev/v1/vulns/CVE-2025-66491
Aliases
Downstream
CGA (8)
MINI (2)
openSUSE (2)
SUSE (1)
Related
openSUSE (2)
SUSE (1)
Published
2025-12-09T00:38:39Z
Modified
2026-10-16T02:57:40Z
Severity
  • 5.9 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N CVSS Calculator
Summary
Traefik has Inverted TLS Verification Logic in its ingress-nginx Provider
Details

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.

Database specific 
{
    "cna_assigner":  "GitHub_M",
    "cwe_ids":  [
        "CWE-295"
    ],
    "osv_generated_from":  "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/66xxx/CVE-2025-66491.json"
}
References

Affected packages

Git / github.com/traefik/traefik

Affected ranges

Type
GIT
Repo
https://github.com/traefik/traefik
Events
Introduced
2cbd96e64c929bea8f933efa75080e9656314f34
Fixed
8a621274b81cd177ea5f6e07a5d5472af7d213b3
Fixed
14a1aedf5704673d875d210d7bacf103a43c77e4
Database specific
Show details 
{
    "extracted_events":  [
        {
            "cpe":  "cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:*",
            "range":  [
                {
                    "introduced":  "3.5.0"
                },
                {
                    "fixed":  "3.6.3"
                }
            ],
            "source":  "CPE_RANGE"
        },
        {
            "range":  [
                {
                    "fixed":  "14a1aedf5704673d875d210d7bacf103a43c77e4"
                }
            ],
            "source":  "REFERENCES_COMMIT"
        },
        {
            "original_tag":  "v3.6.3",
            "range":  [
                {
                    "fixed":  "8a621274b81cd177ea5f6e07a5d5472af7d213b3"
                }
            ],
            "source":  "REFERENCES_TAG"
        }
    ]
}

Database specific

source 
"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-66491.json"