USN-9059-1: ruby-jwt vulnerability

Publication date

11 November 2026

Overview

ruby-jwt could allow unintended access to network services.


Packages

  • ruby-jwt - JSON Web Token implementation in Ruby

Details

It was discovered that ruby-jwt incorrectly verified HMAC signatures when
the verification key was empty or missing. A remote attacker could possibly
use this issue to forge tokens and bypass authentication.

It was discovered that ruby-jwt incorrectly verified HMAC signatures when
the verification key was empty or missing. A remote attacker could possibly
use this issue to forge tokens and bypass authentication.

Update instructions

In general, a standard system update will make all the necessary changes.

Learn more about how to get the fixes.

The problem can be corrected by updating your system to the following package versions:

Ubuntu Release Package Version
26.04 LTS resolute ruby-jwt –  2.7.1-1+deb13u1build0.26.04.1
24.04 LTS noble ruby-jwt –  2.7.1-1+deb13u1build0.24.04.1
22.04 LTS jammy ruby-jwt –  2.2.2-1ubuntu0.1~esm1  
20.04 LTS focal ruby-jwt –  2.1.0-2ubuntu0.1~esm1  
18.04 LTS bionic ruby-jwt –  1.5.6-1ubuntu0.1~esm1  
16.04 LTS xenial ruby-jwt –  1.0.0-3ubuntu0.1~esm1

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