Ipswitch Instant Messaging (IM) 2.0.8.1 and earlier allows remote attackers to cause a denial of service (NULL dereference and application crash) via a version field containing zero.
https://euvd.enisa.europa.eu/vulnerability/EUVD-2008-0951
http://www.securityfocus.com/bid/27677
http://www.securityfocus.com/archive/1/487748/100/200/threaded
http://securityreason.com/securityalert/3697