USN-8018-1: Python vulnerabilities

Publication date

5 February 2026

Overview

Several security issues were fixed in Python.


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
  • python3.4 - An interactive high-level object-oriented language
  • python3.5 - An interactive high-level object-oriented language
  • python3.6 - An interactive high-level object-oriented language
  • python3.7 - 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

Denis Ledoux discovered that Python incorrectly parsed email message
headers. An attacker could possibly use this issue to inject arbitrary
headers into email messages. This issue only affected python3.6, python3.7,
python3.8, python3.9, python3.10, python3.11, python3.12, python3.13, and
python3.14 packages. (CVE-2025-11468)

Jacob Walls, Shai Berger, and Natalia Bidart discovered that Python
inefficiently parsed XML input with quadratic complexity. An attacker could
possibly use this issue to cause a denial of service. (CVE-2025-12084)

It was discovered that Python incorrectly parsed malicious plist files. An
attacker could possibly use this issue to cause Python to use excessive
resources, leading to a denial of service. This issue only affected
python3.5, python3.6, python3.7, python3.8, python3.9, python3.10,
python3.11, python3.12, python3.13,...

Denis Ledoux discovered that Python incorrectly parsed email message
headers. An attacker could possibly use this issue to inject arbitrary
headers into email messages. This issue only affected python3.6, python3.7,
python3.8, python3.9, python3.10, python3.11, python3.12, python3.13, and
python3.14 packages. (CVE-2025-11468)

Jacob Walls, Shai Berger, and Natalia Bidart discovered that Python
inefficiently parsed XML input with quadratic complexity. An attacker could
possibly use this issue to cause a denial of service. (CVE-2025-12084)

It was discovered that Python incorrectly parsed malicious plist files. An
attacker could possibly use this issue to cause Python to use excessive
resources, leading to a denial of service. This issue only affected
python3.5, python3.6, python3.7, python3.8, python3.9, python3.10,
python3.11, python3.12, python3.13, and python3.14 packages.
(CVE-2025-13837)

Omar Hasan discovered that Python incorrectly parsed URL mediatypes. An
attacker could possibly use this issue to inject arbitrary HTTP headers.
(CVE-2025-15282)

Omar Hasan discovered that Python incorrectly parsed malicious IMAP inputs.
An attacker could possibly use this issue to inject arbitrary IMAP
commands. (CVE-2025-15366)

Omar Hasan discovered that Python incorrectly parsed malicious POP3 inputs.
An attacker could possibly use this issue to inject arbitrary POP3
commands. (CVE-2025-15367)

Omar Hasan discovered that Python incorrectly parsed malicious HTTP cookie
headers. An attacker could possibly use this issue to inject arbitrary HTTP
headers. (CVE-2026-0672)

Omar Hasan discovered that Python incorrectly parsed malicious HTTP header
names and values. An attacker could possibly use this issue to inject
arbitrary HTTP headers. (CVE-2026-0865)


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 –  3.13.7-1ubuntu0.3
libpython3.14 –  3.14.0-1ubuntu0.2
python3.13 –  3.13.7-1ubuntu0.3
python3.14 –  3.14.0-1ubuntu0.2
24.04 LTS noble libpython3.12t64 –  3.12.3-1ubuntu0.11
python3.12 –  3.12.3-1ubuntu0.11
22.04 LTS jammy libpython3.10 –  3.10.12-1~22.04.14
libpython3.11 –  3.11.0~rc1-1~22.04.1~esm8  
python3.10 –  3.10.12-1~22.04.14
python3.11 –  3.11.0~rc1-1~22.04.1~esm8  
20.04 LTS focal libpython3.8 –  3.8.10-0ubuntu1~20.04.18+esm5  
libpython3.9 –  3.9.5-3ubuntu0~20.04.1+esm9  
python3.8 –  3.8.10-0ubuntu1~20.04.18+esm5  
python3.9 –  3.9.5-3ubuntu0~20.04.1+esm9  
18.04 LTS bionic libpython3.6 –  3.6.9-1~18.04ubuntu1.13+esm8  
libpython3.7 –  3.7.5-2ubuntu1~18.04.2+esm9  
libpython3.8 –  3.8.0-3ubuntu1~18.04.2+esm9  
python3.6 –  3.6.9-1~18.04ubuntu1.13+esm8  
python3.7 –  3.7.5-2ubuntu1~18.04.2+esm9  
python3.8 –  3.8.0-3ubuntu1~18.04.2+esm9  
16.04 LTS xenial libpython3.5 –  3.5.2-2ubuntu0~16.04.13+esm21  
python3.5 –  3.5.2-2ubuntu0~16.04.13+esm21  
14.04 LTS trusty libpython3.4 –  3.4.3-1ubuntu1~14.04.7+esm19  
libpython3.5 –  3.5.2-2ubuntu0~16.04.4~14.04.1+esm9  
python3.4 –  3.4.3-1ubuntu1~14.04.7+esm19  
python3.5 –  3.5.2-2ubuntu0~16.04.4~14.04.1+esm9  

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