The storageVolUpload function in storage/storage_driver.c in libvirt before 1.2.11 does not check a certain return value, which allows local users to cause a denial of service (NULL pointer dereference and daemon crash) via a crafted offset value in a "virsh vol-upload" command.
http://security.libvirt.org/2014/0009.html
http://secunia.com/advisories/61111
http://lists.opensuse.org/opensuse-updates/2015-01/msg00005.html
http://libvirt.org/git/?p=libvirt.git%3Ba=commit%3Bh=87b9437f8951f9d24f9a85c6bbfff0e54df8c984