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Ubuntu: Python Important Denial Of Service Issue USN-7951-1 CVE-2025

Linuxsecurity •LinuxSecurity Advisories • January 12, 2026

A security issue affects these releases of Ubuntu and its derivatives: - Ubuntu 25.10 - Ubuntu 25.04 - Ubuntu 24.04 LTS - Ubuntu 22.04 LTS - Ubuntu 20.04 LTS - Ubuntu 18.04 LTS Summary: Python could be made to crash if it received specially crafted network traffic. Software Description: - python3.13: An interactive high-level object-oriented language - python3.14: An interactive high-level object-oriented language - python3.12: An interactive high-level object-oriented language - python3.10: An interactive high-level object-oriented language - python3.11: 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.

The problem can be corrected by updating your system to the following package versions: Ubuntu 25.10 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 Ubuntu 25.04 libpython3.13 3.13.3-1ubuntu0.5 python3.13 3.13.3-1ubuntu0.5 Ubuntu 24.04 LTS libpython3.12t64 3.12.3-1ubuntu0.10 python3.12 3.12.3-1ubuntu0.10 Ubuntu 22.04 LTS libpython3.10 3.10.12-1~22.04.13 libpython3.11 3.11.0~rc1-1~22.04.1~esm7 Available with Ubuntu Pro python3.10 3.10.12-1~22.04.13 python3.11 3.11.0~rc1-1~22.04.1~esm7 Available with Ubuntu Pro Ubuntu 20.04 LTS libpython3.8 3.8.10-0ubuntu1~20.04.18+esm4 Available with Ubuntu Pro libpython3.9 3.9.5-3ubuntu0~20.04.1+esm8 Available with Ubuntu Pro python3.8 3.8.10-0ubuntu1~20.04.18+esm4 Available with Ubuntu Pro python3.9 3.9.5-3ubuntu0~20.04.1+esm8 Available with Ubuntu Pro Ubuntu 18.04 LTS libpython3.8 3.8.0-3ubuntu1~18.04.2+esm8 Available with Ubuntu Pro python3.8 3.8.0-3ubuntu1~18.04.2+esm8 Available with Ubuntu Pro In general, a standard system update will make all the necessary changes.

CVE-2025-13836

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This article is one source in a clustered incident — the cluster page carries the summary, timeline and every other outlet covering it.

Python Denial of Service Vulnerability Discovered in HTTP Client A vulnerability in Python's http.client was identified, allowing a malicious server to exploit improper handling of the Content-Length header in HTTP responses. This could lead to excessive memory allocation and result in a denial of service. Affected versions include multiple releases of Ubuntu and its derivatives. 2 sources 29

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Ubuntu: Python Important Denial Of Service Issue USN-7951-1 CVE-2025

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