QEMU is a generic and open source machine emulator and virtualizer.
Heap-based buffer overflow has been found in QEMU’s PCNET controller.
A remote attacker could execute arbitrary code via a specially crafted packets.
There is no known workaround at this time.
All QEMU users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=app-emulation/qemu-2.3.0-r4"