USN-8335-1: pyOpenSSL vulnerability

Publication date

28 May 2026

Overview

pyOpenSSL could allow unintended access to network services.


Packages

  • pyopenssl - Python wrapper around the OpenSSL library

Details

It was discovered that pyOpenSSL incorrectly handled exceptions in the
tlsext_servername callback. This could result in connections being accepted
after an exception, contrary to expectations.

It was discovered that pyOpenSSL incorrectly handled exceptions in the
tlsext_servername callback. This could result in connections being accepted
after an exception, contrary to expectations.

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
20.04 LTS focal python-openssl –  19.0.0-1ubuntu0.1~esm1  
python3-openssl –  19.0.0-1ubuntu0.1~esm1  
18.04 LTS bionic python-openssl –  17.5.0-1ubuntu1+esm1  
python3-openssl –  17.5.0-1ubuntu1+esm1  
16.04 LTS xenial python-openssl –  0.15.1-2ubuntu0.2+esm1  
python3-openssl –  0.15.1-2ubuntu0.2+esm1  

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