ETK-2026-4380Zero's internal tracking ID, independent of the CVE number.

{
  "etk_id": "ETK-2026-4380",
  "cve_id": null,
  "display_id": "ETK-2026-4380",
  "ghsa_id": "GHSA-p956-6gvv-mxqp",
  "euvd_id": null,
  "status": "published",
  "anchor_state": "awaiting_cve",
  "title": "ForwardAuth connection reuse authentication bypass in Traefik",
  "summary": "Traefik ForwardAuth can mishandle Proxy-Authorization credentials when its authentication service uses connection-bound schemes such as NTLM or Negotiate. An unauthenticated client may obtain backend access under another user's identity if ForwardAuth forwards that header to such an authentication service.",
  "mitigation": "Upgrade Traefik v2 to v2.11.62 or later, or v3 to v3.7.18 or later; v3.8.0-rc.2 also includes the fix. If upgrading cannot be done immediately, configure authRequestHeaders to exclude Proxy-Authorization.",
  "vendor": "go",
  "product": "go:github.com/traefik/traefik/v2",
  "affected": [
    {
      "affected_notes": [],
      "affected_ranges": [
        "<= v2.11.61"
      ],
      "ecosystem": "go",
      "fixed_versions": [
        "v2.11.62"
      ],
      "package_name": "github.com/traefik/traefik/v2",
      "purl": "pkg:golang/github.com/traefik/traefik/v2"
    },
    {
      "affected_notes": [],
      "affected_ranges": [
        ">= v3.0.0, <= v3.7.17"
      ],
      "ecosystem": "go",
      "fixed_versions": [
        "v3.7.18"
      ],
      "package_name": "github.com/traefik/traefik/v3",
      "purl": "pkg:golang/github.com/traefik/traefik/v3"
    },
    {
      "affected_notes": [],
      "affected_ranges": [
        ">= v3.8.0-rc.1, <= v3.8.0-rc.1"
      ],
      "ecosystem": "go",
      "fixed_versions": [
        "v3.8.0-rc.2"
      ],
      "package_name": "github.com/traefik/traefik/v3",
      "purl": "pkg:golang/github.com/traefik/traefik/v3"
    }
  ],
  "cwes": [
    287
  ],
  "cvss_score": 7,
  "cvss_src": "cna_vendor",
  "cvss_vector": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N",
  "epss_score": null,
  "epss_percentile": null,
  "epss_asof": null,
  "automation": "contextual",
  "check": false,
  "check_confidence_basis": null,
  "exploit": false,
  "pipeline_minutes": 10.361068783333334,
  "t0_at": null,
  "signals": {
    "trigger_signal": {
      "at": "2026-11-12T10:01:24+00:00",
      "days": -1.4183834015740742,
      "is_lower_bound": true,
      "measured_at": "2026-11-13T20:03:52.380955+00:00",
      "url": "https://github.com/traefik/traefik/security/advisories/GHSA-p956-6gvv-mxqp"
    }
  }
}