Double Precision Courier e-mail MTA allows remote attackers to cause a denial of service (CPU consumption) via a message with an extremely large or negative value for the year, which causes a tight loop.
http://www.securityfocus.com/bid/4908
http://www.iss.net/security_center/static/9228.php
http://sourceforge.net/project/shownotes.php?release_id=93065