The NE2000 emulator in QEMU 0.8.2 allows local users to execute arbitrary code by writing Ethernet frames with a size larger than the MTU to the EN0_TCNT register which triggers a heap-based buffer overflow in the slirp library aka NE2000 \mtu\ heap overflow. NOTE: some sources have used CVE-2007-1321 to refer to this issue as part of \NE2000 network driver and the socket code \ but this is the correct identifier for the mtu overflow vulnerability.