CVE-2026-45363

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.

Affected Software

VendorProductVersion RangeStatus
jwtruby-jwt< 2.10.3affected
jwtruby-jwt>= 3.0.0, < 3.2.0affected

Weaknesses

  • CWE-287: CWE-287: Improper Authentication
  • CWE-326: CWE-326: Inadequate Encryption Strength
  • CWE-1391: CWE-1391: Use of Weak Credentials

References