Ubuntu Security Notices USN-8133-1 USN-8133-1: PyJWT vulnerability Publication date 30 March 2026 Overview PyJWT could allow unintended access to network services. Releases 25.10 24.04 LTS 22.04 LTS 20.04 LTS 18.04 LTS 16.04 LTS Open side navigation Close side navigation Packages Details Update instructions References Packages pyjwt - Python 3 implementation of JSON Web Token Details It was discovered that PyJWT did not validate the critical header parameter, contrary to the RFC specification expectations. A remote attacker could possibly use this issue to bypass certain authentication checks and restrictions. It was discovered that PyJWT did not validate the critical header parameter, contrary to the RFC specification expectations. A remote attacker could possibly use this issue to bypass certain authentication checks and restrictions. 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 25.10 questing python3-jwt – 2.10.1-2ubuntu0.1 24.04 LTS noble python3-jwt – 2.7.0-1ubuntu0.1 22.04 LTS jammy python3-jwt – 2.3.0-1ubuntu0.3 20.04 LTS focal python3-jwt – 1.7.1-2ubuntu2.1+esm1 Ubuntu Pro Fix available with Ubuntu Pro . 18.04 LTS bionic python-jwt – 1.5.3+ds1-1ubuntu0.1+esm1 Ubuntu Pro Fix available with Ubuntu Pro . python3-jwt – 1.5.3+ds1-1ubuntu0.1+esm1 Ubuntu Pro Fix available with Ubuntu Pro . 16.04 LTS xenial python-jwt – 1.3.0-1ubuntu0.1+esm1 Ubuntu Pro Fix available with Ubuntu Pro . python3-jwt – 1.3.0-1ubuntu0.1+esm1 Ubuntu Pro Fix available with Ubuntu Pro . Reduce your security exposure Ubuntu Pro provides ten-year security coverage to 25,000+ packages in Main and Universe repositories, and it is free for up to five machines. Get Ubuntu Pro References CVE-2026-32597 CVE-2026-32597