USN-3456-1: X.Org X server vulnerabilities

17 October 2017

xorg-server, xorg-server-hwe-16.04, xorg-server-lts-xenial vulnerabilities

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

  • Ubuntu 17.04
  • Ubuntu 16.04 LTS
  • Ubuntu 14.04 LTS


Several security issues were fixed in the X.Org X server.

Software Description

  • xorg-server - X.Org X11 server
  • xorg-server-hwe-16.04 - X.Org X11 server
  • xorg-server-lts-xenial - X.Org X11 server


It was discovered that the X.Org X server incorrectly handled certain lengths. An attacker able to connect to an X server, either locally or remotely, could use these issues to crash the server, or possibly execute arbitrary code.

Update instructions

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

Ubuntu 17.04
xserver-xorg-core - 2:1.19.3-1ubuntu1.3
Ubuntu 16.04 LTS
xserver-xorg-core - 2:1.18.4-0ubuntu0.7
xserver-xorg-core-hwe-16.04 - 2:1.19.3-1ubuntu1~16.04.4
Ubuntu 14.04 LTS
xserver-xorg-core - 2:1.15.1-0ubuntu2.11
xserver-xorg-core-lts-xenial - 2:1.18.3-1ubuntu2.3~trusty4

To update your system, please follow these instructions:

After a standard system update you need to reboot your computer to make all the necessary changes.