USN-8897-1: lxml vulnerabilities

Publication date

7 October 2026

Overview

Several security issues were fixed in lxml.


Packages

  • lxml - pythonic binding for the libxml2 and libxslt libraries

Details

Guillem Lefait discovered that lxml incorrectly handled certain URL
attributes. A remote attacker could possibly use this issue to bypass
URL sanitization, leading to a cross-site scripting attack.
(CVE-2026-49825)

Qiu Sihao discovered that lxml incorrectly handled untrusted XML input.
A remote attacker could possibly use this issue to read local files and
expose sensitive information. This issue was only addressed in Ubuntu 24.04
LTS and Ubuntu 26.04 LTS. (CVE-2026-41066)

Guillem Lefait discovered that lxml incorrectly handled certain URL
attributes. A remote attacker could possibly use this issue to bypass
URL sanitization, leading to a cross-site scripting attack.
(CVE-2026-49825)

Qiu Sihao discovered that lxml incorrectly handled untrusted XML input.
A remote attacker could possibly use this issue to read local files and
expose sensitive information. This issue was only addressed in Ubuntu 24.04
LTS and Ubuntu 26.04 LTS. (CVE-2026-41066)

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
26.04 LTS resolute python3-lxml –  6.0.2-1ubuntu0.1
24.04 LTS noble python3-lxml –  5.2.1-1ubuntu0.2
22.04 LTS jammy python3-lxml –  4.8.0-1ubuntu0.1
20.04 LTS focal python-lxml –  4.5.0-1ubuntu0.5+esm1  
python3-lxml –  4.5.0-1ubuntu0.5+esm1  
18.04 LTS bionic python-lxml –  4.2.1-1ubuntu0.6+esm1  
python3-lxml –  4.2.1-1ubuntu0.6+esm1  
16.04 LTS xenial python-lxml –  3.5.0-1ubuntu0.4+esm3  
python3-lxml –  3.5.0-1ubuntu0.4+esm3  
14.04 LTS trusty python-lxml –  3.3.3-1ubuntu0.2+esm6  
python3-lxml –  3.3.3-1ubuntu0.2+esm6  

Reduce your security exposure

Ubuntu Pro provides ten-year security coverage to 25,000+ packages in Main and Universe repositories, and it is free for up to five machines.


Have additional questions?

Talk to a member of the team ›