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

Ubuntu Security Notice USN-3456-1

17th 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 version:

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.


CVE-2017-12176, CVE-2017-12177, CVE-2017-12178, CVE-2017-12179, CVE-2017-12180, CVE-2017-12181, CVE-2017-12182, CVE-2017-12183, CVE-2017-12184, CVE-2017-12185, CVE-2017-12186, CVE-2017-12187