A potential invalid free (uninialized variable) flaw was found in virFileNBDDeviceAssociate function in libvirt.
A remote user able to issue commands to libvirt daemon could use this flaw to crash libvirtd.
This issue did not affect the versions of libvirt package as shipped with Red Hat Enterprise Linux 5 and 6.
Created libvirt tracking bugs for this issue:
Affects: fedora-all [bug 1006511]
libvirt-1.1.3-2.fc20 has been pushed to the Fedora 20 stable repository. If problems still persist, please make note of it in this bug report.