CVE-2026-45363

Publication date 14 July 2026

Last updated 12 November 2026

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

9.1 · Critical

Score breakdown

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.

Status

Package Ubuntu Release Status
ruby-jwt 26.10 stonking
Not affected
26.04 LTS resolute
Fixed in 2.7.1-1+deb13u1build0.26.04.1
24.04 LTS noble
Fixed in 2.7.1-1+deb13u1build0.24.04.1
22.04 LTS jammy
Fixed in 2.2.2-1ubuntu0.1~esm1
20.04 LTS focal
Fixed in 2.1.0-2ubuntu0.1~esm1
18.04 LTS bionic
Fixed in 1.5.6-1ubuntu0.1~esm1
16.04 LTS xenial
Fixed in 1.0.0-3ubuntu0.1~esm1

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Severity score breakdown

CVSS version: CVSS v3.0

Base score 9.1 · Critical

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

References

Related Ubuntu Security Notices (USN)

    • USN-9059-1
    • ruby-jwt vulnerability
    • 11 November 2026

Other references

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