libspice, as used in QEMU-KVM in the Hypervisor (aka rhev-hypervisor) in Red Hat Enterprise Virtualization (RHEV) 2.2 and qspice 0.3.0, does not properly restrict the addresses upon which memory-management actions are performed, which allows guest OS users to cause a denial of service (guest OS crash) or possibly gain privileges via unspecified vectors.
https://bugzilla.redhat.com/show_bug.cgi?id=568701