The remoteClientFreeFunc function in daemon/remote.c in libvirt before 1.1.3, when ACLs are used, does not set an identity, which causes event handler removal to be denied and remote attackers to cause a denial of service (use-after-free and crash) by registering an event handler and then closing the connection.
http://www.securityfocus.com/bid/62972
http://security.libvirt.org/2013/0013.html
http://security.gentoo.org/glsa/glsa-201412-04.xml
http://secunia.com/advisories/60895
http://libvirt.org/git/?p=libvirt.git%3Ba=commit%3Bh=8294aa0c1750dcb49d6345cd9bd97bf421580d8b