The xen packages contain administration tools and the xend service for managing the kernel-xen kernel for virtualization on Red Hat Enterprise Linux. An out-of-bounds memory access flaw was found in the way QEMU"s virtual Floppy Disk Controller handled FIFO buffer access while processing certain FDC commands. A privileged guest user could use this flaw to crash the guest or, potentially, execute arbitrary code on the host with the privileges of the host"s QEMU process corresponding to the guest. Red Hat would like to thank Jason Geffner of CrowdStrike for reporting this issue. All xen users are advised to upgrade to these updated packages, which contain a backported patch to correct this issue. After installing the updated packages, all running fully-virtualized guests must be restarted for this update to take effect.