The SISCO OSI stack, as used in SISCO MMS-EASE, ICCP Toolkit for MMS-EASE, AX-S4 MMS and AX-S4 ICCP, and possibly other control system applications, allows remote attackers to cause a denial of service (application termination and restart) via malformed packets.
http://www.vupen.com/english/advisories/2007/0237
http://www.securityfocus.com/bid/22095
http://www.kb.cert.org/vuls/id/MIMG-6TUHTT
http://www.kb.cert.org/vuls/id/145825