Format string vulnerability in the FTP server for Novell Netware 6.0 SP1 (NWFTPD) allows remote attackers to cause a denial of service (ABEND) via format strings in the USER command.
http://www.securityfocus.com/bid/5099
http://www.iss.net/security_center/static/9429.php
http://online.securityfocus.com/archive/1/278689
http://archives.neohapsis.com/archives/vulnwatch/2002-q2/0127.html