The xen packages contain administration tools and the xend service for managing the kernel-xen kernel for virtualization on Red Hat Enterprise Linux. A heap overflow flaw was found in the way QEMU emulated the e1000 network interface card. A privileged guest user in a virtual machine whose network interface is configured to use the e1000 emulated driver could use this flaw to crash QEMU or, possibly, escalate their privileges on the host. Red Hat would like to thank Nicolae Mogoreanu for reporting this issue. This update also fixes the following bugs: * Adding support for jumbo frames introduced incorrect network device expansion when a bridge is created. The expansion worked correctly with the default configuration, but could have caused network setup failures when a user-defined network script was used. This update changes the expansion so network setup will not fail, even when a user-defined network script is used. * A bug was found in xenconsoled, the Xen hypervisor console daemon. If timestamp logging for this daemon was enabled , xenconsoled could crash if the guest emitted a lot of information to its serial console in a short period of time. Eventually, the guest would freeze after the console buffer was filled due to the crashed xenconsoled. Timestamp logging is disabled by default. All xen users are advised to upgrade to these updated packages, which contain backported patches to correct these issues. The system must be rebooted for this update to take effect.