{
  "cveId": "CVE-2025-59420",
  "url": "https://patchblox.com/security/cve/CVE-2025-59420",
  "summary": "CVE-2025-59420 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2025-59420, released September 22, 2025. It is not reported as exploited. Patch Radar priority: High.",
  "title": "python-authlib: Authlib is a Python library which builds OAuth and OpenID Connect servers",
  "description": "Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to version 1.6.4, Authlib\u2019s JWS verification accepts tokens that declare unknown critical header parameters (crit), violating RFC 7515 \u201Cmust\u2011understand\u201D semantics. An attacker can craft a signed token with a critical header (for example, bork or cnf) that strict verifiers reject but Authlib accepts. In mixed\u2011language fleets, this enables split\u2011brain verification and can lead to policy bypass, replay, or privilege escalation. This issue has been patched in version 1.6.4.",
  "published": "2025-09-22T11:15:00Z",
  "severity": "high",
  "cvss": 7.5,
  "cvssVector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
  "epss": 0.00275,
  "epssPercentile": 0.20012,
  "priority": "High",
  "priorityTier": 3,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "python-authlib",
      "release": "Debian 12.15 (bookworm)",
      "fixedVersion": "1.2.0-1\u002Bdeb12u1",
      "fix": "DEBIAN-CVE-2025-59420",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2025-59420",
      "released": "2025-09-22T18:15:46Z"
    },
    {
      "platform": "linux",
      "product": "python-authlib",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "1.6.0-1\u002Bdeb13u1",
      "fix": "DEBIAN-CVE-2025-59420",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2025-59420",
      "released": "2025-09-22T18:15:46Z"
    },
    {
      "platform": "linux",
      "product": "python-authlib",
      "release": "Debian 14",
      "fixedVersion": "1.6.4-1",
      "fix": "DEBIAN-CVE-2025-59420",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2025-59420",
      "released": "2025-09-22T18:15:46Z"
    },
    {
      "platform": "linux",
      "product": "python3-authlib",
      "release": "Ubuntu 22.04.1 LTS (jammy)",
      "fixedVersion": "0.15.5-1ubuntu0.1~esm1",
      "fix": "python3-authlib 0.15.5-1ubuntu0.1~esm1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-jammy-python3-authlib-0.15.5-1ubuntu0.1-esm1",
      "released": "2025-10-22T15:15:00Z"
    },
    {
      "platform": "linux",
      "product": "python3-authlib",
      "release": "Ubuntu 24.04.5 LTS (noble)",
      "fixedVersion": "1.3.0-1ubuntu0.1~esm1",
      "fix": "python3-authlib 1.3.0-1ubuntu0.1~esm1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-noble-python3-authlib-1.3.0-1ubuntu0.1-esm1",
      "released": "2026-01-08T10:15:00Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-09T07:25:28Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}