USN-8939-1: libXtst vulnerabilities

Publication date

19 October 2026

Overview

Several security issues were fixed in libXtst.


Packages

  • libxtst - X11 Record extension library

Details

It was discovered that libXtst did not properly handle certain RECORD
replies from the X server. A malicious X server could possibly use this
issue to cause libXtst clients to crash, resulting in a denial of service.
(CVE-2026-94286)

Tobias Stoeckmann discovered that libXtst did not properly handle certain
memory operations. A malicious X server could possibly use this issue to
cause libXtst to access memory out of bounds, resulting in a denial of
service. This issue only affected Ubuntu 16.04 LTS. (CVE-2016-7951)

Tobias Stoeckmann discovered that libXtst did not properly handle certain
replies from the X server. A malicious X server could possibly use this
issue to cause libXtst to enter an infinite loop, resulting in a denial of
service. This issue only affected Ubuntu 16.04 LTS. (CVE-2016-7952)

It was discovered that libXtst did not properly handle certain RECORD
replies from the X server. A malicious X server could possibly use this
issue to cause libXtst clients to crash, resulting in a denial of service.
(CVE-2026-94286)

Tobias Stoeckmann discovered that libXtst did not properly handle certain
memory operations. A malicious X server could possibly use this issue to
cause libXtst to access memory out of bounds, resulting in a denial of
service. This issue only affected Ubuntu 16.04 LTS. (CVE-2016-7951)

Tobias Stoeckmann discovered that libXtst did not properly handle certain
replies from the X server. A malicious X server could possibly use this
issue to cause libXtst to enter an infinite loop, resulting in a denial of
service. This issue only affected Ubuntu 16.04 LTS. (CVE-2016-7952)

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
26.10 stonking libxtst-dev –  2:1.2.5-1ubuntu1
libxtst6 –  2:1.2.5-1ubuntu1
26.04 LTS resolute libxtst-dev –  2:1.2.5-1ubuntu0.1
libxtst6 –  2:1.2.5-1ubuntu0.1
24.04 LTS noble libxtst-dev –  2:1.2.3-1.1ubuntu0.1
libxtst6 –  2:1.2.3-1.1ubuntu0.1
22.04 LTS jammy libxtst-dev –  2:1.2.3-1ubuntu0.22.04.1
libxtst6 –  2:1.2.3-1ubuntu0.22.04.1
20.04 LTS focal libxtst-dev –  2:1.2.3-1ubuntu0.20.04.1~esm1  
libxtst6 –  2:1.2.3-1ubuntu0.20.04.1~esm1  
18.04 LTS bionic libxtst-dev –  2:1.2.3-1ubuntu0.18.04.1~esm1  
libxtst6 –  2:1.2.3-1ubuntu0.18.04.1~esm1  
16.04 LTS xenial libxtst-dev –  2:1.2.2-1ubuntu0.1~esm1  
libxtst6 –  2:1.2.2-1ubuntu0.1~esm1  

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