USN-7951-1: Python vulnerability

Publication date

12 January 2026

Overview

Python could be made to crash if it received specially crafted network traffic.


Packages

  • python3.10 - An interactive high-level object-oriented language
  • python3.11 - An interactive high-level object-oriented language
  • python3.12 - An interactive high-level object-oriented language
  • python3.13 - An interactive high-level object-oriented language
  • python3.14 - An interactive high-level object-oriented language
  • python3.8 - An interactive high-level object-oriented language
  • python3.9 - An interactive high-level object-oriented language

Details

It was discovered that Python's http.client did not properly handle the
Content-Length header in HTTP responses. A malicious server could exploit
this to cause Python to allocate excessive memory, leading to a denial of
service.

It was discovered that Python's http.client did not properly handle the
Content-Length header in HTTP responses. A malicious server could exploit
this to cause Python to allocate excessive memory, leading to a denial of
service.

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 libpython3.13 –  3.13.7-1ubuntu0.2
libpython3.14 –  3.14.0-1ubuntu0.1
python3.13 –  3.13.7-1ubuntu0.2
python3.14 –  3.14.0-1ubuntu0.1
25.04 plucky libpython3.13 –  3.13.3-1ubuntu0.5
python3.13 –  3.13.3-1ubuntu0.5
24.04 LTS noble libpython3.12t64 –  3.12.3-1ubuntu0.10
python3.12 –  3.12.3-1ubuntu0.10
22.04 LTS jammy libpython3.10 –  3.10.12-1~22.04.13
libpython3.11 –  3.11.0~rc1-1~22.04.1~esm7  
python3.10 –  3.10.12-1~22.04.13
python3.11 –  3.11.0~rc1-1~22.04.1~esm7  
20.04 LTS focal libpython3.8 –  3.8.10-0ubuntu1~20.04.18+esm4  
libpython3.9 –  3.9.5-3ubuntu0~20.04.1+esm8  
python3.8 –  3.8.10-0ubuntu1~20.04.18+esm4  
python3.9 –  3.9.5-3ubuntu0~20.04.1+esm8  
18.04 LTS bionic libpython3.8 –  3.8.0-3ubuntu1~18.04.2+esm8  
python3.8 –  3.8.0-3ubuntu1~18.04.2+esm8  

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