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[USN-9059-1] ruby-jwt vulnerability

Posted on 12 November 2026
Ubuntu Security

==========================================================================Ubuntu Security Notice USN-9059-1
November 11, 2026

ruby-jwt vulnerability
==========================================================================
A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 26.04 LTS
- Ubuntu 24.04 LTS
- Ubuntu 22.04 LTS
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS

Summary:

ruby-jwt could allow unintended access to network services.

Software Description:
- 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.

Update instructions:

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

Ubuntu 26.04 LTS
ruby-jwt 2.7.1-1+deb13u1build0.26.04.1

Ubuntu 24.04 LTS
ruby-jwt 2.7.1-1+deb13u1build0.24.04.1

Ubuntu 22.04 LTS
ruby-jwt 2.2.2-1ubuntu0.1~esm1
Available with Ubuntu Pro

Ubuntu 20.04 LTS
ruby-jwt 2.1.0-2ubuntu0.1~esm1
Available with Ubuntu Pro

Ubuntu 18.04 LTS
ruby-jwt 1.5.6-1ubuntu0.1~esm1
Available with Ubuntu Pro

Ubuntu 16.04 LTS
ruby-jwt 1.0.0-3ubuntu0.1~esm1
Available with Ubuntu Pro

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

References:
https://ubuntu.com/security/notices/USN-9059-1
CVE-2026-45363

Package Information:
https://launchpad.net/ubuntu/+source/ruby-jwt/2.7.1-1+deb13u1build0.26.04.1
https://launchpad.net/ubuntu/+source/ruby-jwt/2.7.1-1+deb13u1build0.24.04.1

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