Double free vulnerability in the qemuAgentGetVCPUs function in qemu/qemu_agent.c in libvirt 1.0.6 through 1.1.0 allows remote attackers to cause a denial of service (daemon crash) via a cpu count request, as demonstrated by the "virsh vcpucount dom --guest" command.
https://bugzilla.redhat.com/show_bug.cgi?id=986383
http://openwall.com/lists/oss-security/2013/07/19/11
http://libvirt.org/git/?p=libvirt.git%3Ba=commitdiff%3Bh=dfc692350a04a70b4ca65667c30869b3bfdaf034