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.
https://exchange.xforce.ibmcloud.com/vulnerabilities/38238
http://www.vupen.com/english/advisories/2007/1597
http://www.securityfocus.com/bid/23731
http://www.mandriva.com/security/advisories?name=MDVSA-2008:162
http://www.mandriva.com/security/advisories?name=MDKSA-2007:203
http://www.debian.org/security/2007/dsa-1284
http://www.attrition.org/pipermail/vim/2007-October/001842.html
http://taviso.decsystem.org/virtsec.pdf
http://secunia.com/advisories/33568
http://secunia.com/advisories/29129
http://secunia.com/advisories/27486
http://secunia.com/advisories/25095
http://secunia.com/advisories/25073
http://lists.opensuse.org/opensuse-security-announce/2009-01/msg00004.html