Buffer overflow in Pragma Systems TelnetServer 2000 version 4.0 allows remote attackers to cause a denial of service via a long series of null characters to the rexec port.
InterAccess TelnetD Server 4.0 allows remote attackers to conduct a denial of service via malformed terminal client configuration information.
telnetd.exe in Pragma TelnetServer 7.0.4.589 allows remote attackers to cause a denial of service (process crash and resource exhaustion) via a crafted TELOPT PRAGMA LOGON telnet option, which triggers a NULL pointer dereference.