USN-7974-1: libxml2 vulnerabilities

Publication date

22 January 2026

Overview

Several security issues were fixed in libxml2.


Packages

Details

It was discovered that libxml2 incorrectly handled maliciously crafted SGML
catalog files. An attacker could possibly use this issue to cause libxml2
to consume excessive resources, leading to a denial of service.
(CVE-2025-8732)

It was discovered that libxml2 incorrectly handled recursive include
directories with the RelaxNG parser. An attacker could possibly use this
issue to cause libxml2 to consume excessive resources, leading to a denial
of service. (CVE-2026-0989)

Nick Wellnhofer discovered that libxml2 incorrectly parsed catalogs with
self-referencing URI delegates. An attacker could possibly use this issue
to cause libxml2 to consume excessive resources, leading to a denial of
service. (CVE-2026-0990)

Nick Wellnhofer discovered that libxml2 inefficiently parsed catalogs
linked with repeating...

It was discovered that libxml2 incorrectly handled maliciously crafted SGML
catalog files. An attacker could possibly use this issue to cause libxml2
to consume excessive resources, leading to a denial of service.
(CVE-2025-8732)

It was discovered that libxml2 incorrectly handled recursive include
directories with the RelaxNG parser. An attacker could possibly use this
issue to cause libxml2 to consume excessive resources, leading to a denial
of service. (CVE-2026-0989)

Nick Wellnhofer discovered that libxml2 incorrectly parsed catalogs with
self-referencing URI delegates. An attacker could possibly use this issue
to cause libxml2 to consume excessive resources, leading to a denial of
service. (CVE-2026-0990)

Nick Wellnhofer discovered that libxml2 inefficiently parsed catalogs
linked with repeating nextCatalog elements. An attacker could possibly use
this issue to cause libxml2 to use excessive resources, leading to a denial
of service. (CVE-2026-0992)


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 libxml2-16 –  2.14.5+dfsg-0.2ubuntu0.1
24.04 LTS noble libxml2 –  2.9.14+dfsg-1.3ubuntu3.7
22.04 LTS jammy libxml2 –  2.9.13+dfsg-1ubuntu0.11
20.04 LTS focal libxml2 –  2.9.10+dfsg-5ubuntu0.20.04.10+esm4  
18.04 LTS bionic libxml2 –  2.9.4+dfsg1-6.1ubuntu1.9+esm7  
16.04 LTS xenial libxml2 –  2.9.3+dfsg1-1ubuntu0.7+esm12  
14.04 LTS trusty libxml2 –  2.9.1+dfsg1-3ubuntu4.13+esm11  

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.


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