The QXL display driver in QXL Virtual GPU 0.1.0 allows local users to cause a denial of service (guest crash or hang) via a SPICE connection that prevents other threads from obtaining the qemu_mutex mutex. NOTE: some of these details are obtained from third party information.
https://wiki.mageia.org/en/Support/Advisories/MGASA-2013-0036
https://exchange.xforce.ibmcloud.com/vulnerabilities/81704
https://bugzilla.redhat.com/show_bug.cgi?id=906032
http://www.ubuntu.com/usn/USN-1714-1
http://www.openwall.com/lists/oss-security/2013/01/30/4
http://www.openwall.com/lists/oss-security/2013/01/30/3
http://www.mandriva.com/security/advisories?name=MDVSA-2013:138