USN-8133-1: PyJWT vulnerability

Publication date

30 March 2026

Overview

PyJWT could allow unintended access to network services.


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  
18.04 LTS bionic python-jwt –  1.5.3+ds1-1ubuntu0.1+esm1  
python3-jwt –  1.5.3+ds1-1ubuntu0.1+esm1  
16.04 LTS xenial python-jwt –  1.3.0-1ubuntu0.1+esm1  
python3-jwt –  1.3.0-1ubuntu0.1+esm1  

Reduce your security exposure

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