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.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||
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| jwt | ruby-jwt | affected |
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Advisories
| Source | ID | Title |
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 Github GHSA |
GHSA-c32j-vqhx-rx3x | ruby-jwt: Empty-key HMAC bypass; cross-language sibling of CVE-2026-44351 |
Fixes
Solution
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Workaround
No workaround given by the vendor.
References
History
Tue, 14 Jul 2026 21:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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. | |
| Title | `jwt` (Ruby gem) - empty-key HMAC bypass | |
| Weaknesses | CWE-1391 CWE-287 CWE-326 |
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| Metrics |
cvssV3_1
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Projects
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MITRE
Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-07-14T21:34:05.174Z
Reserved: 2026-05-12T00:51:29.085Z
Link: CVE-2026-45363
Vulnrichment
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NVD
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Redhat
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OpenCVE Enrichment
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