Etype Eserv 2.97 allows remote attackers to cause a denial of service (resource exhaustion) via a large number of PASV commands that consume ports 1024 through 5000, which prevents the server from accepting valid PASV.
The (1) FTP, (2) POP3, (3) SMTP, and (4) NNTP servers in EServer 2.92 through 2.97, and possibly 2.98, allow remote attackers to cause a denial of service (crash) via a large amount of data.