=========================================================================
Ubuntu Security Notice USN-7694-1
August 14, 2025

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

- Ubuntu 25.04
- Ubuntu 24.04 LTS
- Ubuntu 22.04 LTS
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS
- Ubuntu 14.04 LTS

Summary:

Several security issues were fixed in libxml2.

Software Description:
- libxml2: GNOME XML library

Details:

Ahmed Lekssays discovered that libxml2 did not properly perform certain
mathematical operations, leading to an integer overflow. An attacker
could possibly use this issue to cause a crash, resulting in a denial of
service, or possibly execute arbitrary code. (CVE-2025-6021)

Ahmed Lekssays discovered that libxml2 did not properly validate the size
of an untrusted input stream. An attacker could possibly use this issue
to cause a crash, resulting in a denial of service, or possibly execute
arbitrary code. (CVE-2025-6170)

Nikita Sveshnikov discovered that libxml2 did not properly handle certain
XPath expressions, leading to a use-after-free vulnerability. An attacker
could potentially exploit this issue to cause a denial of service.
(CVE-2025-49794)

Nikita Sveshnikov discovered that libxml2 contained a type confusion
vulnerability when parsing specially crafted XML documents. An attacker
could potentially exploit this issue to cause a denial of service.
(CVE-2025-49796)

Update instructions:

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

Ubuntu 25.04
  libxml2                         2.12.7+dfsg+really2.9.14-0.4ubuntu0.2
  python3-libxml2                 2.12.7+dfsg+really2.9.14-0.4ubuntu0.2

Ubuntu 24.04 LTS
  libxml2                         2.9.14+dfsg-1.3ubuntu3.4
  python3-libxml2                 2.9.14+dfsg-1.3ubuntu3.4

Ubuntu 22.04 LTS
  libxml2                         2.9.13+dfsg-1ubuntu0.8
  python3-libxml2                 2.9.13+dfsg-1ubuntu0.8

Ubuntu 20.04 LTS
  libxml2                         2.9.10+dfsg-5ubuntu0.20.04.10+esm1
                                  Available with Ubuntu Pro
  python3-libxml2                 2.9.10+dfsg-5ubuntu0.20.04.10+esm1
                                  Available with Ubuntu Pro

Ubuntu 18.04 LTS
  libxml2                         2.9.4+dfsg1-6.1ubuntu1.9+esm4
                                  Available with Ubuntu Pro
  python-libxml2                  2.9.4+dfsg1-6.1ubuntu1.9+esm4
                                  Available with Ubuntu Pro
  python3-libxml2                 2.9.4+dfsg1-6.1ubuntu1.9+esm4
                                  Available with Ubuntu Pro

Ubuntu 16.04 LTS
  libxml2                         2.9.3+dfsg1-1ubuntu0.7+esm9
                                  Available with Ubuntu Pro
  python-libxml2                  2.9.3+dfsg1-1ubuntu0.7+esm9
                                  Available with Ubuntu Pro

Ubuntu 14.04 LTS
  libxml2                         2.9.1+dfsg1-3ubuntu4.13+esm8
                                  Available with Ubuntu Pro
  python-libxml2                  2.9.1+dfsg1-3ubuntu4.13+esm8
                                  Available with Ubuntu Pro

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

References:
  https://ubuntu.com/security/notices/USN-7694-1
  CVE-2025-49794, CVE-2025-49796, CVE-2025-6021, CVE-2025-6170

Package Information:
  https://launchpad.net/ubuntu/+source/libxml2/2.12.7+dfsg+really2.9.14-0.4ubuntu0.2
  https://launchpad.net/ubuntu/+source/libxml2/2.9.14+dfsg-1.3ubuntu3.4
  https://launchpad.net/ubuntu/+source/libxml2/2.9.13+dfsg-1ubuntu0.8