Buffer overflow in hw/pt-msi.c in Xen 4.6.x and earlier, when using the qemu-xen-traditional (aka qemu-dm) device model, allows local x86 HVM guest administrators to gain privileges by leveraging a system with access to a passed-through MSI-X capable physical PCI device and MSI-X table entries, related to a "write path."
https://security.gentoo.org/glsa/201604-03
http://xenbits.xen.org/xsa/advisory-164.html
http://www.securitytracker.com/id/1034481
http://www.securityfocus.com/bid/79579
http://www.oracle.com/technetwork/topics/security/ovmbulletinjul2016-3090546.html