CVE-2026-102271

{
  "etk_id": "ETK-2026-19",
  "cve_id": "CVE-2026-102271",
  "display_id": "CVE-2026-102271",
  "ghsa_id": "GHSA-p4g4-x82p-q773",
  "euvd_id": "EUVD-2026-88539",
  "status": "published",
  "anchor_state": "anchored",
  "title": "DER key confusion in PyJWT token verification",
  "summary": "PyJWT versions 2.4.0 through 2.13.0 can treat DER-encoded asymmetric public-key material as an HMAC verification secret. An attacker with the public key may create accepted tokens if the application permits both HS* and asymmetric algorithms for the same DER byte key. PyJWK and PyJWKClient users are not affected by this condition.",
  "mitigation": "Upgrade PyJWT to version 2.14.0 or later. Restrict each verification path to its intended algorithm family and do not use asymmetric public-key bytes as HMAC secrets.",
  "vendor": "pip",
  "product": "pip:PyJWT",
  "affected": [
    {
      "affected_notes": [],
      "affected_ranges": [
        "2.13.0"
      ],
      "ecosystem": "pip",
      "fixed_versions": [
        "2.14.0"
      ],
      "package_name": "pyjwt",
      "purl": "pkg:pypi/pyjwt"
    }
  ],
  "cwes": [
    347
  ],
  "cvss_score": 7.4,
  "cvss_src": "cna_vendor",
  "cvss_vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N",
  "epss_score": 0.0018,
  "epss_percentile": 0.0718,
  "epss_asof": "2026-10-20",
  "automation": "contextual",
  "check": true,
  "check_confidence_basis": "mechanism_verified",
  "exploit": false,
  "pipeline_minutes": 12.890036766666666,
  "t0_at": "2026-09-28T20:31:53.066000+00:00",
  "signals": {
    "check": {
      "at": "2026-09-29T21:33:23.729763+00:00",
      "days": 1.042716015775463,
      "is_lower_bound": false,
      "measured_at": "2026-09-28T20:31:53.066000+00:00",
      "url": null
    },
    "public_poc": {
      "at": "2026-09-29T23:14:33+00:00",
      "days": 1.1129621990740741,
      "is_lower_bound": false,
      "measured_at": "2026-09-28T20:31:53.066000+00:00",
      "url": "https://github.com/advisories/GHSA-p4g4-x82p-q773"
    },
    "trigger_signal": {
      "at": "2026-09-28T20:31:53.066000+00:00",
      "days": 0,
      "is_lower_bound": false,
      "measured_at": "2026-09-28T20:31:53.066000+00:00",
      "url": "https://github.com/jpadilla/pyjwt/security/advisories/GHSA-p4g4-x82p-q773"
    }
  }
}