The translate_hierarchy_event function in x11/clutter-device-manager-xi2.c in Clutter, when resuming the system, does not properly handle XIQueryDevice errors when a device has "disappeared," which causes the gnome-shell to crash and allows physically proximate attackers to access the previous gnome-shell session via unspecified vectors.
https://bugzilla.redhat.com/show_bug.cgi?id=980111
https://bugzilla.gnome.org/show_bug.cgi?id=701974
http://www.openwall.com/lists/oss-security/2013/06/19/1
http://lists.opensuse.org/opensuse-updates/2013-10/msg00014.html