The problem can be corrected by upgrading the affected package to
version 4.16-1ubuntu3.1 (for Ubuntu 4.10), or 4.16-1ubuntu11.1 (for
Ubuntu 5.04). After a standard system upgrade you need to restart your
session to effect the necessary changes.
In some cases, xscreensaver did not properly grab the keyboard when
reading the password for unlocking the screen, so that the password
was typed into the currently active application window.
The only known vulnerable case was when xscreensaver activated while
an rdesktop session was currently active.