Integer overflow in the virtio_net_handle_mac function in hw/net/virtio-net.c in QEMU 2.0 and earlier allows local guest users to execute arbitrary code via a MAC addresses table update request, which triggers a heap-based buffer overflow.
https://bugzilla.redhat.com/show_bug.cgi?id=1078846
http://www.ubuntu.com/usn/USN-2182-1
http://www.debian.org/security/2014/dsa-2910
http://www.debian.org/security/2014/dsa-2909
http://thread.gmane.org/gmane.comp.emulators.qemu/266713
http://secunia.com/advisories/58191