The libxlDomainGetNumaParameters function in the libxl driver (libxl/libxl_driver.c) in libvirt before 1.2.1 does not properly initialize the nodemap, which allows local users to cause a denial of service (invalid free operation and crash) or possibly execute arbitrary code via an inactive domain to the virsh numatune command.
https://www.redhat.com/archives/libvir-list/2013-December/msg01258.html
https://www.redhat.com/archives/libvir-list/2013-December/msg01176.html
https://bugzilla.redhat.com/show_bug.cgi?id=1048629
http://www.ubuntu.com/usn/USN-2093-1
http://security.gentoo.org/glsa/glsa-201412-04.xml
http://secunia.com/advisories/60895
http://lists.opensuse.org/opensuse-updates/2014-02/msg00060.html