GAMSoft TelSrv telnet server 1.5 and earlier allows remote attackers to cause a denial of service via a long username.
https://exchange.xforce.ibmcloud.com/vulnerabilities/4945
https://euvd.enisa.europa.eu/vulnerability/EUVD-2000-0661
http://www.securityfocus.com/bid/1478
http://archives.neohapsis.com/archives/ntbugtraq/2000-q3/0056.html
http://archives.neohapsis.com/archives/ntbugtraq/2000-q3/0031.html