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.
openSUSE Leap 42.2 SUSE Linux Enterprise Desktop 12 SP1 SUSE Linux Enterprise for SAP 12 SUSE Linux Enterprise for SAP 12 SP1 SUSE Linux Enterprise Server 12 SP1 SUSE Linux Enterprise Server 12 SP1-LTSS SUSE Linux Enterprise Server 12-LTSS SUSE Linux Enterprise Server for SAP Applications 12 SUSE Linux Enterprise Server for SAP Applications 12 SP1 SUSE Linux Enterprise Server for SAP Applications 12 SP1-LTSS SUSE Linux Enterprise Server for SAP Applications 12-LTSS SUSE OpenStack Cloud 6