Red Hat Security Advisory 2012-0370-01 - 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.
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