UltraBoard 1.6 and other versions allow remote attackers to cause a denial of service by referencing UltraBoard in the Session parameter, which causes UltraBoard to fork copies of itself.
UltraBoard.pl or UltraBoard.cgi CGI scripts in UltraBoard 1.6 allows remote attackers to read arbitrary files via a pathname string that includes a dot dot (..) and ends with a null byte.