Red Hat Security Advisory 2016-2963-01 – Xen is a virtual machine monitor Security Fix: An out of bounds array access issue was found in the Xen virtual machine monitor, built with the QEMU ioport support. It could occur while doing ioport read/write operations, if guest was to supply a 32bit address parameter. A privileged guest user/process could use this flaw to potentially escalate their privileges on a host.