Mandriva Linux Security Advisory – A problem with the way xscreensaver verifies user passwords was discovered by Alex Yamauchi. When a system is using remote authentication (i.e. LDAP) for logins, a local attacker able to cause a network outage on the system could cause xscreensaver to crash, which would unlock the screen.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/56427/MDKSA-2007-097.txt
Source: https://packetstormsecurity.com/files/56427/Mandriva-Linux-Security-Advisory-2007.097.html