The qemuDomainGetBlockIoTune function in qemu/qemu_driver.c in libvirt before 1.2.9, when a disk has been hot-plugged or removed from the live image, allows remote attackers to cause a denial of service (crash) or read sensitive heap information via a crafted blkiotune query, which triggers an out-of-bounds read.
http://lists.opensuse.org/opensuse-updates/2014-10/msg00014.html
http://lists.opensuse.org/opensuse-updates/2014-10/msg00017.html
http://rhn.redhat.com/errata/RHSA-2014-1352.html
http://secunia.com/advisories/60291
http://secunia.com/advisories/60895
http://security.gentoo.org/glsa/glsa-201412-04.xml