USN-8872-1: libxmltok vulnerabilities

Publication date

5 October 2026

Overview

libxmltok could be made to crash if it opened a specially crafted file.


Packages

  • libxmltok - XML Parser Toolkit, developer libraries

Details

It was discovered that Expat, contained with the xmltok library did not
correctly handle certain integer arithmetic. If a user or automated
system were tricked into opening a specially crafted file, an attacker
could possibly cause a denial of service. (CVE-2026-56404, CVE-2026-56405)

It was discovered that Expat, contained with the xmltok library did not
correctly handle certain integer arithmetic. If a user or automated
system were tricked into opening a specially crafted file, an attacker
could possibly cause a denial of service. (CVE-2026-56404, CVE-2026-56405)

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
24.04 LTS noble libxmltok1-dev –  1.2-4.1ubuntu2.24.0.4.1+esm5  
libxmltok1t64 –  1.2-4.1ubuntu2.24.0.4.1+esm5  
22.04 LTS jammy libxmltok1 –  1.2-4ubuntu0.22.04.1~esm7  
libxmltok1-dev –  1.2-4ubuntu0.22.04.1~esm7  
20.04 LTS focal libxmltok1 –  1.2-4ubuntu0.20.04.1~esm7  
libxmltok1-dev –  1.2-4ubuntu0.20.04.1~esm7  
18.04 LTS bionic libxmltok1 –  1.2-4ubuntu0.18.04.1~esm7  
libxmltok1-dev –  1.2-4ubuntu0.18.04.1~esm7  
16.04 LTS xenial libxmltok1 –  1.2-3ubuntu0.1~esm1
libxmltok1-dev –  1.2-3ubuntu0.1~esm1

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