(RHSA-2015:1087) Important: qemu-kvm security update

KVM (Kernel-based Virtual Machine) is a full virtualization solution for
Linux on AMD64 and Intel 64 systems. The qemu-kvm package provides the
user-space component for running virtual machines using KVM.

A flaw was found in the way QEMU’s AMD PCnet Ethernet emulation handled
multi-TMD packets with a length above 4096 bytes. A privileged guest user
in a guest with an AMD PCNet ethernet card enabled could potentially use
this flaw to execute arbitrary code on the host with the privileges of the
hosting QEMU process. (CVE-2015-3209)

Red Hat would like to thank Matt Tait of Google’s Project Zero security
team for reporting this issue.

All qemu-kvm users are advised to upgrade to these updated packages, which
contain a backported patch to correct this issue. After installing this
update, shut down all running virtual machines. Once all virtual machines
have shut down, start them again for this update to take effect.