Ubuntu Security Notice 907-1 – It was discovered that gnome-screensaver did not correctly lock all screens when monitors get hotplugged. An attacker with physical access could use this flaw to gain access to a locked session. It was discovered that gnome-screensaver did not correctly handle keyboard grab when monitors get hotplugged. An attacker with physical access could use this flaw to gain access to a locked session. This issue only affected Ubuntu 9.10.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/86986/USN-907-1.txt
Source: https://packetstormsecurity.com/files/86986/Ubuntu-Security-Notice-907-1.html