1. Ubuntu Security Notices
  2. USN-4966-2

USN-4966-2: libx11 vulnerability

Publication date

25 May 2021

Overview

libx11 could allow unintended access to services.

Releases

Packages

  • libx11 - X11 client-side library

Details

USN-4966-1 fixed a vulnerability in libx11. This update provides
the corresponding update for Ubuntu 14.04 ESM and Ubuntu 16.04 ESM.

Original advisory details:

It was discovered that libx11 incorrectly validated certain parameter
lengths. A remote attacker could possibly use this issue to trick libx11
into emitting extra X protocol requests.

USN-4966-1 fixed a vulnerability in libx11. This update provides
the corresponding update for Ubuntu 14.04 ESM and Ubuntu 16.04 ESM.

Original advisory details:

It was discovered that libx11 incorrectly validated certain parameter
lengths. A remote attacker could possibly use this issue to trick libx11
into emitting extra X protocol requests.

Update instructions

After a standard system update you need to reboot your computer to 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
16.04 xenial libx11-6 –  2:1.6.3-1ubuntu2.2+esm1  
14.04 trusty libx11-6 –  2:1.6.2-1ubuntu2.1+esm2  

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References

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