Ubuntu Security Notice 278-1 – Marcus Meissner discovered a race condition in gdm’s handling of the ~/.ICEauthority file permissions. A local attacker could exploit this to become the owner of an arbitrary file in the system. When getting control over automatically executed scripts (like cron jobs), the attacker could eventually leverage this flaw to execute arbitrary commands with root privileges.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/46099/USN-278-1.txt
Source: https://packetstormsecurity.com/files/46099/Ubuntu-Security-Notice-278-1.html