CVE-2017-10917: xen: NULL pointer deref in event channel poll (XSA-221)

Severity: Critical

CVSS Score: 9.1

Xen through 4.8.x does not validate the port numbers of polled event channel ports, which allows guest OS users to cause a denial of service (NULL pointer dereference and host OS crash) or possibly obtain sensitive information, aka XSA-221.