Mandriva Linux Security Advisory 2010-109 – gdk/gdkwindow.c in GTK+ before 2.18.5, as used in gnome-screensaver before 2.28.1, performs implicit paints on windows of type GDK_WINDOW_FOREIGN, which triggers an X error in certain circumstances and consequently allows physically proximate attackers to bypass screen locking and access an unattended workstation by pressing the Enter key many times. This update fixes this issue.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/90020/MDVSA-2010-109.txt
Source: https://packetstormsecurity.com/files/90020/Mandriva-Linux-Security-Advisory-2010-109.html