FKIE_CVE-2026-45363

Vulnerability from fkie_nvd - Published: 2026-07-14 22:16 - Updated: 2026-07-15 14:18
Severity
9.1 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Summary
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.
References
security-advisories@github.comhttps://github.com/jwt/ruby-jwt/commit/9820020869ad147b941e49d96ab8beba35532964
security-advisories@github.comhttps://github.com/jwt/ruby-jwt/commit/db560b769a07bd9724e77ff505011ac01872106f
security-advisories@github.comhttps://github.com/jwt/ruby-jwt/releases/tag/v2.10.3
security-advisories@github.comhttps://github.com/jwt/ruby-jwt/releases/tag/v3.2.0
security-advisories@github.comhttps://github.com/jwt/ruby-jwt/security/advisories/GHSA-c32j-vqhx-rx3x
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "ruby-jwt",
          "vendor": "jwt",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 2.10.3"
            },
            {
              "status": "affected",
              "version": "\u003e= 3.0.0, \u003c 3.2.0"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "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, \u0027\u0027, true, algorithm: \u0027HS256\u0027) accepts an attacker-forged token because OpenSSL::HMAC.digest(\u0027SHA256\u0027, \u0027\u0027, 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",
  "lastModified": "2026-07-15T14:18:11.470",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 9.1,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.2,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-45363",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-07-15T13:24:12.081532Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-07-14T22:16:54.463",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/jwt/ruby-jwt/commit/9820020869ad147b941e49d96ab8beba35532964"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/jwt/ruby-jwt/commit/db560b769a07bd9724e77ff505011ac01872106f"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/jwt/ruby-jwt/releases/tag/v2.10.3"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/jwt/ruby-jwt/releases/tag/v3.2.0"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/jwt/ruby-jwt/security/advisories/GHSA-c32j-vqhx-rx3x"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-287"
        },
        {
          "lang": "en",
          "value": "CWE-326"
        },
        {
          "lang": "en",
          "value": "CWE-1391"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}



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