UBUNTU-CVE-2026-45363

Advisory lineage Upstream: 1 Downstream: 0
Upstream
CVE-2026-45363
Published: 14 Jul 2026, 22:16
Last modified:15 Jul 2026, 19:47

Vulnerability Summary

Overall Risk (default)
high
70/100
CVSS Score
9.1 CRITICAL
3.1 (osv_ubuntu)
EPSS Score
No data
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

14 Jul 2026, 22:16
Published
Vulnerability first disclosed
15 Jul 2026, 19:47
Last Modified
Vulnerability information updated

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 Metrics

  • v3.1•CRITICAL•Score: 9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected Systems

  • ubuntu•ruby-jwt

    all | all | all | all | all | all

References (7)