Critical
ruby-jwt — security advisory
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.
- Products
- ruby-jwt
- Affected versions
- 1.0.0-3, 1.5.6-1, 2.1.0-2, 2.2.2-1, 2.7.0-2, 2.7.1-1, 3.2.0-1
- Fixed versions
- Not specified
- CVEs
- CVE-2026-45363
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 02:14 UTC · Revision 1
Source evidence
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.
osv:UBUNTU-CVE-2026-45363
ruby-jwt
Fixed versions: Not specified
ruby-jwt
Fixed versions: Not specified
ruby-jwt
Fixed versions: Not specified
ruby-jwt
Fixed versions: Not specified
ruby-jwt
Fixed versions: Not specified
ruby-jwt
Fixed versions: Not specified
ruby-jwt
Fixed versions: Not specified
Complete source record
{
"id": "0feb55e428c05227465dfd4599d86c7e635323e26c84c76567d1b9831a9ab47b",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-45363",
"method": "structured",
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"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.",
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"aliases": [
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"metrics": [
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"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"
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"modified": "2026-10-17T12:58:22.902289792Z",
"provider": "osv",
"upstream": [
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],
"references": [
"https://ubuntu.com/security/CVE-2026-45363",
"https://www.cve.org/CVERecord?id=CVE-2026-45363",
"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"
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"source_id": "core-osv",
"document_id": 358635,
"published_at": "2026-07-14T22:16:00+00:00"
}