{"cve":"CVE-2026-45363","nvd":{"published":"2026-07-14T22:16:54.463","modified":"2026-10-24T22:10:00.210","status":"Deferred","description":"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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","score":9.1},"cwes":["CWE-287","CWE-326","CWE-1391"],"references":["https://github.com/jwt/ruby-jwt/commit/9820020869ad147b941e49d96ab8beba35532964","https://github.com/jwt/ruby-jwt/commit/db560b769a07bd9724e77ff505011ac01872106f","https://github.com/jwt/ruby-jwt/releases/tag/v2.10.3","https://github.com/jwt/ruby-jwt/releases/tag/v3.2.0","https://github.com/jwt/ruby-jwt/security/advisories/GHSA-c32j-vqhx-rx3x"],"products":[],"source":"nvd","synced_at":"2026-10-25T17:50:06.907763985+00:00"},"epss":{"cve":"CVE-2026-45363","score":0.00364,"percentile":0.30012,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-c32j-vqhx-rx3x","url":"https://osv.dev/vulnerability/GHSA-c32j-vqhx-rx3x","summary":"ruby-jwt: Empty-key HMAC bypass; cross-language sibling of CVE-2026-44351","modified":"2026-09-10T03:50:46.749617476Z","packages":[{"ecosystem":"RubyGems","name":"jwt","purl":"pkg:gem/jwt","ranges":[">=3.0.0 <3.2.0"],"fixed":["3.2.0"]},{"ecosystem":"RubyGems","name":"jwt","purl":"pkg:gem/jwt","ranges":["<2.10.3"],"fixed":["2.10.3"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}