Default configuration in Matt Wright FormHandler.cgi script allows arbitrary directories to be used for attachments, and only restricts access to the /etc/ directory, which allows remote attackers to read arbitrary files via the reply_message_attach attachment parameter.
Matt Wright's download.cgi 1.0 allows remote attackers to read arbitrary files via a .. (dot dot) in the f parameter.
Matt Wright's FormMail CGI script allows remote attackers to obtain environmental variables via the env_report parameter.