The virDomainListPopulate function in conf/domain_conf.c in libvirt before 1.2.9 does not clean up the lock on the list of domains, which allows remote attackers to cause a denial of service (deadlock) via a NULL value in the second parameter in the virConnectListAllDomains API command.
libvirt.org/git/?p=libvirt.git%3Ba=commitdiff%3Bh=fc22b2e74890873848b43fffae43025d22053669
lists.opensuse.org/opensuse-updates/2014-10/msg00014.html
lists.opensuse.org/opensuse-updates/2014-10/msg00017.html
rhn.redhat.com/errata/RHSA-2014-1352.html
secunia.com/advisories/60291
secunia.com/advisories/62303
security.libvirt.org/2014/0005.html
www.ubuntu.com/usn/USN-2404-1