The remote host is vulnerable to a buffer overflow.
This host is running a version of WS_FTP FTP server prior to 3.1.2. Versions earlier than 3.1.2 contain an unchecked buffer in routines that handle the 'CPWD' command arguments. The 'CPWD' command allows remote users to change their password. By issuing a malformed argument to the CPWD command, a user could overflow a buffer and execute arbitrary code on this host. Note that a local user account is required.
Upgrade to version 3.1.2 or higher.