{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": "cpe:2.3:a:pyjwt_project:pyjwt:*:*:*:*:*:*:*:*",
            "extracted_events": [
              {
                "introduced": "2.9.0"
              },
              {
                "fixed": "2.13.0"
              },
              {
                "fixed": "2.12.1"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "CPE_RANGE"
            ]
          },
          "events": [
            {
              "introduced": "868cf4ab2ca5a0a39da40e5a14dd740b203662b2"
            },
            {
              "fixed": "7144e4534c34810f4525dc4578a32addd8212cff"
            }
          ],
          "repo": "https://github.com/jpadilla/pyjwt",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-jq35-7prp-9v3f"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-347"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48523.json"
  },
  "details": "PyJWT is a JSON Web Token implementation in Python. From 2.9.0 to 2.12.1, there is a verifier-side algorithm allow-list bypass when jwt.decode() or jwt.decode_complete() are called with a PyJWK key. The token header alg is checked against the caller-supplied algorithms allow-list, but signature verification is performed with the algorithm bound to the PyJWK object instead of the header algorithm. An attacker who controls a registered JWK/JWKS private key can sign with a disallowed algorithm, advertise an allowed algorithm in the JWT header, and still be accepted. The issue affects the documented PyJWKClient.get_signing_key_from_jwt(...) flow. This vulnerability is fixed in 2.13.0.",
  "id": "CVE-2026-48523",
  "modified": "2026-07-15T01:49:19.953220961Z",
  "published": "2026-05-28T15:10:19.141Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48523.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/jpadilla/pyjwt/security/advisories/GHSA-jq35-7prp-9v3f"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-48523"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "PyJWT: Algorithm allow-list bypass when decoding with `PyJWK` / `PyJWKClient` keys"
}