An issue was discovered in Xen through 4.14.x. There is a lack of preemption in evtchn_reset() / evtchn_destroy(). In particular, the FIFO event channel model allows guests to have a large number of event channels active at a time. Closing all of these (when resetting all event channels or when cleaning up after the guest) may take extended periods of time. So far, there was no arrangement for preemption at suitable intervals, allowing a CPU to spend an almost unbounded amount of time in the processing of these operations. Malicious or buggy guest kernels can mount a Denial of Service (DoS) attack affecting the entire system. All Xen versions are vulnerable in principle. Whether versions 4.3 and older are vulnerable depends on underlying hardware characteristics.
Image SLES15-SP1-Manager-4-0-EC2-HVM-BYOS-Proxy Image SLES15-SP1-Manager-4-0-EC2-HVM-BYOS-Server Image SLES15-SP2-Manager-4-1-Proxy-BYOS-Azure Image SLES15-SP2-Manager-4-1-Proxy-BYOS-EC2-HVM Image SLES15-SP2-Manager-4-1-Proxy-BYOS-GCE Image SLES15-SP2-Manager-4-1-Server-BYOS-Azure Image SLES15-SP2-Manager-4-1-Server-BYOS-EC2-HVM Image SLES15-SP2-Manager-4-1-Server-BYOS-GCE openSUSE Leap 15.2 openSUSE Leap 15.3 openSUSE Leap 15.4 openSUSE Tumbleweed SUSE CaaS Platform 4.0 SUSE Linux Enterprise Desktop 15 SP1 SUSE Linux Enterprise Desktop 15 SP2 SUSE Linux Enterprise Desktop 15 SP3 SUSE Linux Enterprise Desktop 15 SP4 SUSE Linux Enterprise Desktop 15 SP5 SUSE Linux Enterprise High Performance Computing 15 SP1 SUSE Linux Enterprise High Performance Computing 15 SP2 SUSE Linux Enterprise High Performance Computing 15 SP3 SUSE Linux Enterprise High Performance Computing 15 SP4 SUSE Linux Enterprise High Performance Computing 15 SP5 SUSE Linux Enterprise High Performance Computing 15-ESPOS SUSE Linux Enterprise High Performance Computing 15-LTSS SUSE Linux Enterprise Module for Basesystem 15 SP1 SUSE Linux Enterprise Module for Basesystem 15 SP2 SUSE Linux Enterprise Module for Basesystem 15 SP3 SUSE Linux Enterprise Module for Basesystem 15 SP4 SUSE Linux Enterprise Module for Basesystem 15 SP5 SUSE Linux Enterprise Module for Open Buildservice Development Tools 15 SP1 SUSE Linux Enterprise Module for Open Buildservice Development Tools 15 SP2 SUSE Linux Enterprise Module for Server Applications 15 SP1 SUSE Linux Enterprise Module for Server Applications 15 SP2 SUSE Linux Enterprise Module for Server Applications 15 SP3 SUSE Linux Enterprise Module for Server Applications 15 SP4 SUSE Linux Enterprise Point of Sale 12 SP2-CLIENT SUSE Linux Enterprise Server 11 SP4-LTSS SUSE Linux Enterprise Server 12 SP2-BCL SUSE Linux Enterprise Server 12 SP2-ESPOS SUSE Linux Enterprise Server 12 SP2-LTSS SUSE Linux Enterprise Server 12 SP3-BCL SUSE Linux Enterprise Server 12 SP3-ESPOS SUSE Linux Enterprise Server 12 SP3-LTSS SUSE Linux Enterprise Server 12 SP3-TERADATA SUSE Linux Enterprise Server 12 SP4-ESPOS SUSE Linux Enterprise Server 12 SP4-LTSS SUSE Linux Enterprise Server 12 SP5 SUSE Linux Enterprise Server 15 SP1 SUSE Linux Enterprise Server 15 SP2 SUSE Linux Enterprise Server 15 SP3 SUSE Linux Enterprise Server 15 SP4 SUSE Linux Enterprise Server 15 SP5 SUSE Linux Enterprise Server 15-LTSS SUSE Linux Enterprise Server for SAP Applications 11 SP4-LTSS SUSE Linux Enterprise Server for SAP Applications 12 SP2 SUSE Linux Enterprise Server for SAP Applications 12 SP2-BCL SUSE Linux Enterprise Server for SAP Applications 12 SP2-ESPOS SUSE Linux Enterprise Server for SAP Applications 12 SP2-LTSS SUSE Linux Enterprise Server for SAP Applications 12 SP3 SUSE Linux Enterprise Server for SAP Applications 12 SP3-BCL SUSE Linux Enterprise Server for SAP Applications 12 SP3-ESPOS SUSE Linux Enterprise Server for SAP Applications 12 SP3-LTSS SUSE Linux Enterprise Server for SAP Applications 12 SP3-TERADATA SUSE Linux Enterprise Server for SAP Applications 12 SP4 SUSE Linux Enterprise Server for SAP Applications 12 SP4-ESPOS SUSE Linux Enterprise Server for SAP Applications 12 SP4-LTSS SUSE Linux Enterprise Server for SAP Applications 12 SP5 SUSE Linux Enterprise Server for SAP Applications 15 SUSE Linux Enterprise Server for SAP Applications 15 SP1 SUSE Linux Enterprise Server for SAP Applications 15 SP2 SUSE Linux Enterprise Server for SAP Applications 15 SP3 SUSE Linux Enterprise Server for SAP Applications 15 SP4 SUSE Linux Enterprise Server for SAP Applications 15 SP5 SUSE Linux Enterprise Software Development Kit 12 SP5 SUSE Linux Enterprise Storage 6 SUSE Linux Enterprise Storage 7 SUSE Linux Enterprise Storage 7.1 SUSE Manager Proxy 4.0 SUSE Manager Proxy 4.1 SUSE Manager Proxy 4.2 SUSE Manager Proxy 4.3 SUSE Manager Retail Branch Server 4.0 SUSE Manager Retail Branch Server 4.1 SUSE Manager Retail Branch Server 4.2 SUSE Manager Retail Branch Server 4.3 SUSE Manager Server 4.0 SUSE Manager Server 4.1 SUSE Manager Server 4.2 SUSE Manager Server 4.3 SUSE OpenStack Cloud 7 SUSE OpenStack Cloud 8 SUSE OpenStack Cloud 9 SUSE OpenStack Cloud Crowbar 8 SUSE OpenStack Cloud Crowbar 9