Several security issues were fixed in the X.Org X server.
Ilja van Sprundel discovered a multitude of security issues in the X.Org X server. An attacker able to connect to an X server, either locally or remotely, could use these issues to cause the X server to crash or execute arbitrary code resulting in possible privilege escalation.
9 December 2014
A security issue affects these releases of Ubuntu and its derivatives:
Several security issues were fixed in the X.Org X server.
Ilja van Sprundel discovered a multitude of security issues in the X.Org X server. An attacker able to connect to an X server, either locally or remotely, could use these issues to cause the X server to crash or execute arbitrary code resulting in possible privilege escalation.
The problem can be corrected by updating your system to the following package versions:
To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.
After a standard system update you need to reboot your computer to make all the necessary changes.
Vulmon