IPSwitch IMail Web Calendaring service (iwebcal) allows remote attackers to cause a denial of service (crash) via an HTTP POST request without a Content-Length field.
https://euvd.enisa.europa.eu/vulnerability/EUVD-2002-1065
http://www.securityfocus.com/bid/5365
http://www.iss.net/security_center/static/9722.php
http://archives.neohapsis.com/archives/bugtraq/2002-07/0399.html