EUVD Vulnerability Catalog
EUVD-2026-44516
Severity: CRITICAL
Base Score: 9.1
CVSS Version: 3.1
Vulnerability 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 Vector Analysis
Below is the complete, human-readable breakdown of the CVSS metric string: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
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Attack Vector (AV): Network
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Attack Complexity (AC): Low
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Privileges Required (PR): None
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User Interaction (UI): None
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Scope (S): Unchanged
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Confidentiality Impact (C): High
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Integrity Impact (I): High
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Availability Impact (A): None
Affected Vendors & Systems
Vendor
jwt
References & Advisory Links
- https://github.com/jwt/ruby-jwt/security/advisories/GHSA-c32j-vqhx-rx3x
- 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
Metadata Profile
Database Authority
European Union Agency for Cybersecurity (ENISA) EUVD
Assigner
GitHub_M
EPSS Probability
0.24
Known Aliases
CVE-2026-45363
GHSA-c32j-vqhx-rx3x
Published On
2026-07-14
Last Updated
2026-09-19