Ubuntu Update for Linux kernel vulnerabilities USN-537-2
Please Install the Updated Packages.
USN-537-1 fixed vulnerabilities in gnome-screensaver. The fixes were incomplete, and only reduced the scope of the vulnerability, without fully solving it. This update fixes related problems in compiz. Original advisory details: Jens Askengren discovered that gnome-screensaver became confused when running under Compiz, and could lose keyboard lock focus. A local attacker could exploit this to bypass the user's locked screen saver.
compiz vulnerability on Ubuntu 7.10