The host_from_stream_offset function in arch_init.c in QEMU, when loading RAM during migration, allows remote attackers to execute arbitrary code via a crafted (1) offset or (2) length value in savevm data.
http://git.qemu.org/?p=qemu.git;a=commit;h=0be839a2701369f669532ea5884c15bead1c6e08
http://rhn.redhat.com/errata/RHSA-2015-0349.html
http://rhn.redhat.com/errata/RHSA-2015-0624.html
http://thread.gmane.org/gmane.comp.emulators.qemu/306117