freeFTPd 1.0.10 allows remote authenticated users to cause a denial of service (null dereference and crash) via a PORT command with missing arguments.
https://euvd.enisa.europa.eu/vulnerability/EUVD-2005-3807
http://www.vupen.com/english/advisories/2005/2580
http://www.securityfocus.com/bid/15557