Xen 4.2.x and 4.1.x does not properly restrict access to IRQs, which allows local stub domain clients to gain access to IRQs and cause a denial of service via vectors related to "passed-through IRQs or PCI devices."
http://www.securityfocus.com/bid/59292
http://www.openwall.com/lists/oss-security/2013/04/18/6
http://www.debian.org/security/2013/dsa-2662
http://security.gentoo.org/glsa/glsa-201309-24.xml
http://secunia.com/advisories/55082
http://lists.opensuse.org/opensuse-updates/2013-06/msg00049.html
http://lists.opensuse.org/opensuse-security-announce/2014-03/msg00021.html
http://lists.fedoraproject.org/pipermail/package-announce/2013-May/104538.html
http://lists.fedoraproject.org/pipermail/package-announce/2013-May/104537.html