=========================================================================Ubuntu Security Notice USN-1950-1
September 12, 2013

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

- Ubuntu 13.04

Summary:

Light Display Manager could be made to expose sensitive information.

Software Description:
- lightdm: Display Manager

Details:

It was discovered that Light Display Manager created .Xauthority files with
incorrect permissions. A local attacker could use this flaw to bypass
access restrictions.

Update instructions:

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

Ubuntu 13.04:
  lightdm                         1.6.0-0ubuntu3.1

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

References:
  
  CVE-2013-4331

Package Information:
  https://launchpad.net/ubuntu/+source/lightdm/1.6.0-0ubuntu3.1