# CVE-2026-114656: Traefik before 2.11.58 and 3.7.13 mTLS Bypass via Negated Host Matcher

Status: published. Published: 2026-10-22. Updated: 2026-11-04.

Traefik before 2.11.58 and 3.7.13 contains an authentication bypass vulnerability that allows unauthenticated clients to skip client-certificate checks because negated Host matchers are counted as served domains. Attackers can reach backends protected by RequireAndVerifyClientCert when a router rule with !Host() creates a TLS options conflict that falls back to the default options.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: disclosure@vulncheck.com) — https://github.com/traefik/traefik/security/advisories/GHSA-2272-4vv8-65ww

## Affected products and versions

- traefik / traefik (github.com/traefik/traefik/v2): ≥ 0; < 2.11.58 (affected, semver); 2.11.58 (unaffected, semver). Source: CNA: VulnCheck
- traefik / traefik (github.com/traefik/traefik/v3): ≥ 3.0.0; < 3.7.13 (affected, semver); 3.7.13 (unaffected, semver). Source: CNA: VulnCheck

## NVD configuration conditions

Affected CPE matches depend on the following AND/OR and negation conditions:

```json
[
  {
    "negate": false,
    "nodes": [
      {
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "2.11.58",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "3.7.13",
            "versionStartIncluding": "3.0.0",
            "vulnerable": true
          }
        ],
        "negate": false,
        "operator": "OR"
      }
    ],
    "operator": "OR"
  }
]
```

## Severity and prioritization

- CVSS 4.0: 6.9 (medium); CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:L/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 7.5 (high); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:L/A:N; source: CNA: VulnCheck

- CVSS 4.0: 6.9 (medium); CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X; source: NVD: disclosure@vulncheck.com

- CVSS 3.1: 9.3 (critical); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N; source: NVD: nvd@nist.gov

- CVSS 3.1: 7.5 (high); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:L/A:N; source: NVD: disclosure@vulncheck.com

- CISA KEV: No listing in collected sources

- EPSS: 0.15% as of 2026-11-04; percentile 4.60%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-436

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/traefik/traefik/security/advisories/GHSA-2272-4vv8-65ww (CNA: VulnCheck; vendor-advisory)

- https://www.vulncheck.com/advisories/traefik-before-2.11.58-and-3.7.13-mtls-bypass-via-negated-host-matcher (CNA: VulnCheck; third-party-advisory)

- https://github.com/traefik/traefik/security/advisories/GHSA-2272-4vv8-65ww (disclosure@vulncheck.com; Patch, Vendor Advisory)

- https://www.vulncheck.com/advisories/traefik-before-2.11.58-and-3.7.13-mtls-bypass-via-negated-host-matcher (disclosure@vulncheck.com; Third Party Advisory)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-114656; retrieved 2026-11-04; source updated 2026-11-04

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-114656; retrieved 2026-11-04; source updated 2026-11-04

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-114656; retrieved 2026-11-04; source updated Not reported

Revision: cad3e326648e4542c95c0712a985e5aca98f71605e7484dbe029a66ec528d4b8

Canonical: https://y2.dev/cve/CVE-2026-114656

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