spice-gtk 0.14, and possibly other versions, invokes the polkit authority using the insecure polkit_unix_process_new API function, which allows local users to bypass intended access restrictions by leveraging a PolkitUnixProcess PolkitSubject race condition via a (1) setuid process or (2) pkexec process, a related issue to CVE-2013-4288.
http://www.securityfocus.com/bid/62538
http://www.openwall.com/lists/oss-security/2013/09/18/6
http://secunia.com/advisories/54947
http://rhn.redhat.com/errata/RHSA-2013-1273.html
http://lists.opensuse.org/opensuse-updates/2013-10/msg00031.html