{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "2.10.3"
              },
              {
                "introduced": "3.0.0"
              },
              {
                "fixed": "3.2.0"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "introduced": "b987a5152732ab43d9e16558d3343ffca4c36cb1"
            },
            {
              "fixed": "a52e81d2c6b6aa6ff4be929dfa69da6b52db2888"
            },
            {
              "fixed": "db560b769a07bd9724e77ff505011ac01872106f"
            },
            {
              "fixed": "9820020869ad147b941e49d96ab8beba35532964"
            }
          ],
          "repo": "https://github.com/jwt/ruby-jwt",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-c32j-vqhx-rx3x"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-1391",
      "CWE-287",
      "CWE-326"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45363.json"
  },
  "details": "ruby-jwt is a Ruby implementation of the RFC 7519 OAuth JSON Web Token standard. Prior to 2.10.3 and 3.2.0, JWT.decode(token, '', true, algorithm: 'HS256') accepts an attacker-forged token because OpenSSL::HMAC.digest('SHA256', '', payload) returns a valid digest under an empty key and no empty-key precondition exists in the HMAC algorithm. The same path is reached when a keyfinder block or key_finder: argument returns an empty string, nil, or an array containing nil for an unknown key, affecting HS256, HS384, and HS512 verification through JWT.decode and JWT::EncodedToken#verify_signature!. This issue is fixed in versions 2.10.3 and 3.2.0.",
  "id": "CVE-2026-45363",
  "modified": "2026-07-17T03:41:37.579912362Z",
  "published": "2026-07-14T21:32:26.676Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/jwt/ruby-jwt/releases/tag/v2.10.3"
    },
    {
      "type": "WEB",
      "url": "https://github.com/jwt/ruby-jwt/releases/tag/v3.2.0"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45363.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/jwt/ruby-jwt/security/advisories/GHSA-c32j-vqhx-rx3x"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-45363"
    },
    {
      "type": "FIX",
      "url": "https://github.com/jwt/ruby-jwt/commit/9820020869ad147b941e49d96ab8beba35532964"
    },
    {
      "type": "FIX",
      "url": "https://github.com/jwt/ruby-jwt/commit/db560b769a07bd9724e77ff505011ac01872106f"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "`jwt` (Ruby gem) - empty-key HMAC bypass"
}