[USN-7852-2] libxml2 vulnerability

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Ubuntu Security Notice USN-7852-2
November 27, 2025

libxml2 vulnerability
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS

Summary:

libxml2 could be made to crash or run programs if it opened a specially crafted file.

Software Description:
- libxml2: GNOME XML library

Details:

USN-7582-1 fixed a vulnerability in libxml2. This update provides the
corresponding fix for Ubuntu 16.04 LTS, Ubuntu 18.04 LTS and
Ubuntu 20.04 LTS.

Original advisory details:

It was discovered that libxslt, used by libxml2, incorrectly handled
certain attributes. An attacker could use this issue to cause a crash,
resulting in a denial of service, or possibly execute arbitrary code. This
update adds a fix to libxml2 to mitigate the libxslt vulnerability.

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 20.04 LTS
libxml2 2.9.10+dfsg-5ubuntu0.20.04.10+esm3
Available with Ubuntu Pro
python-libxml2 2.9.10+dfsg-5ubuntu0.20.04.10+esm3
Available with Ubuntu Pro
python3-libxml2 2.9.10+dfsg-5ubuntu0.20.04.10+esm3
Available with Ubuntu Pro

Ubuntu 18.04 LTS
libxml2 2.9.4+dfsg1-6.1ubuntu1.9+esm6
Available with Ubuntu Pro
python-libxml2 2.9.4+dfsg1-6.1ubuntu1.9+esm6
Available with Ubuntu Pro
python3-libxml2 2.9.4+dfsg1-6.1ubuntu1.9+esm6
Available with Ubuntu Pro

Ubuntu 16.04 LTS
libxml2 2.9.3+dfsg1-1ubuntu0.7+esm11
Available with Ubuntu Pro
python-libxml2 2.9.3+dfsg1-1ubuntu0.7+esm11
Available with Ubuntu Pro

In general, a standard system update will make all the necessary changes.

References:
https://ubuntu.com/security/notices/USN-7852-2
https://ubuntu.com/security/notices/USN-7852-1
CVE-2025-7425