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)
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.
--