Off-by-one error in the cmd_smart function in the smart self test in hw/ide/core.c in QEMU before 2.0 allows local users to have unspecified impact via a SMART EXECUTE OFFLINE command that triggers a buffer underflow and memory corruption.
Integer overflow in the virtio_net_handle_mac function in hw/net/virtio-net.c in QEMU 2.0 and earlier allows local guest users to execute arbitrary code via a MAC addresses table update request, which triggers a heap-based buffer overflow.