Xen 4.2.x, 4.1.x, and 4.0, when using Intel VT-d for PCI passthrough, does not properly configure VT-d when supporting a device that is behind a legacy PCI Bridge, which allows local guests to cause a denial of service to other guests by injecting an interrupt.
http://www.openwall.com/lists/oss-security/2013/01/09/5
http://www.debian.org/security/2013/dsa-2636
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-updates/2013-04/msg00052.html
http://lists.opensuse.org/opensuse-updates/2013-04/msg00051.html
http://lists.opensuse.org/opensuse-security-announce/2014-03/msg00021.html