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Ubuntu 25.04, 24.04, 22.04: Critical libxml2 Denial of Service Issues

ubuntu
Calendar Grey August 20, 2025
Dist Ubuntu Esm H88
Enhance your Ubuntu system's security against libxml2 vulnerabilities by following these steps: update packages, upgrade, clean unused dependencies, and reboot.
Several security issues were fixed in libxml2.

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 document...

Read the Full Advisory

Topics%20covered

Topics Covered

security advisory DoS Ubuntu integer overflow libxml2 use-after-free

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

Severity
critical
Lowest
Low
Medium
High
Critical

Ubuntu Security Notice USN-7694-1

Topics%20covered

Topics Covered

security advisory DoS Ubuntu integer overflow libxml2 use-after-free

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

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