Xen Security Advisory CVE-2017-10920 CVE-2017-10921 CVE-2017-10922 [grant table operations mishandle reference counts]
Description: The grant-table feature in Xen through 4.8.x does not ensure sufficient type counts for a GNTMAP_device_map and GNTMAP_host_map mapping, which allows guest OS users to cause a denial of service (count mismanagement and memory corruption) or obtain privileged host OS access, aka XSA-224 bug 2.
Impact: For the worst issue, a PV guest could gain a writeable mapping of its own pagetable, allowing it to escalate its privileges to that of the host.
Mitigation: Updates are available. Please check specific vendor advisory for more information.