Buffer overflow in NET$CSMACD.EXE in HP OpenVMS 8.3 and earlier allows local users to cause a denial of service (machine crash) via the "MCR MCL SHOW CSMA-CD Port * All" command, which overwrites a Non-Paged Pool Packet.
http://www.vupen.com/english/advisories/2007/3382
http://www.securityfocus.com/bid/25939
http://secunia.com/advisories/27084