Red Hat Enterprise Virtualization Manager (RHEV-M) before 3.1, in certain unspecified conditions, does not lock the desktop screen between SPICE sessions, which allows local users with access to a virtual machine to gain access to other users' desktop sessions via unspecified vectors.
https://bugzilla.redhat.com/show_bug.cgi?id=754876
http://www.securitytracker.com/id?1027838
http://www.securityfocus.com/bid/56825