CVE-2026-45363

{
  "id": "CVE-2026-45363",
  "sourceIdentifier": "[email protected]",
  "published": "2026-07-14T22:16:54.463",
  "lastModified": "2026-10-24T22:10:00.210",
  "vulnStatus": "Deferred",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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."
    },
    {
      "lang": "es",
      "value": "ruby-jwt es una implementación en Ruby del estándar RFC 7519 OAuth JSON Web Token. Antes de las versiones 2.10.3 y 3.2.0, JWT.decode(token, ’’, true, algorithm: ’HS256’) acepta un token forjado por un atacante porque OpenSSL::HMAC.digest(’SHA256’, ’’, payload) devuelve un digest válido con una clave vacía y no existe ninguna precondición de clave vacía en el algoritmo HMAC. Se alcanza la misma ruta cuando un bloque keyfinder o un argumento key_finder: devuelve una cadena vacía, nil, o un array que contiene nil para una clave desconocida, afectando la verificación de HS256, HS384 y HS512 a través de JWT.decode y JWT::EncodedToken#verify_signature!. Este problema está solucionado en las versiones 2.10.3 y 3.2.0."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "jwt",
          "product": "ruby-jwt",
          "versions": [
            {
              "version": "< 2.10.3",
              "status": "affected"
            },
            {
              "version": ">= 3.0.0, < 3.2.0",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
          "baseScore": 9.1,
          "baseSeverity": "CRITICAL",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "availabilityImpact": "NONE"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.2
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-07-15T13:24:12.081532Z",
          "id": "CVE-2026-45363",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-287"
        },
        {
          "lang": "en",
          "value": "CWE-326"
        },
        {
          "lang": "en",
          "value": "CWE-1391"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/jwt/ruby-jwt/commit/9820020869ad147b941e49d96ab8beba35532964",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/jwt/ruby-jwt/commit/db560b769a07bd9724e77ff505011ac01872106f",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/jwt/ruby-jwt/releases/tag/v2.10.3",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/jwt/ruby-jwt/releases/tag/v3.2.0",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/jwt/ruby-jwt/security/advisories/GHSA-c32j-vqhx-rx3x",
      "source": "[email protected]"
    },
    {
      "url": "https://lists.debian.org/debian-lts-announce/2026/09/msg00022.html",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ]
}