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://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2014-3633