source: https://www.securityfocus.com/bid/5899/info

PowerFTP server is a shareware ftp server available for the Microsoft Windows platform. It is distributed and maintained by Cooolsoft.

It has been reported that PowerFTP server does not properly handle long user names. When excessive data is supplied as an argument to the FTP 'USER' command, the server becomes unstable. Exploitation of this vulnerability typically results in a crash of the server, requiring a manual restart to resume FTP service.

https://github.com/offensive-security/exploitdb-bin-sploits/raw/master/bin-sploits/21909.tgz