Gentoo Linux Security Advisory 201612-56 - Multiple vulnerabilities have been found in Xen, the worst of which could lead to the execution of arbitrary code on the host system. Versions less than 4.7.1-r4 are affected.
70ed2e55c553c06ec58463cd484b2a108097349e02fa9a442b32774e3342fa47
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.
7ac655efdee02ef89e17a23c7ecd9abe6845f56392eefc7adbc10532877a2365