Stored XSS vulnerability in synType CMS comment text field

Vulnerability ID: HTB22417
Reference: http://www.htbridge.ch/advisory/stored_xss_vulnerability_in_syntype_cms_comment_text_field.html
Product: synType CMS
Vendor: MindArray GbR
Vulnerable Version: V.0.12.2 and Probably Prior Versions
Vendor Notification: 03 June 2010
Vulnerability Type: Stored 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 text saving script to properly sanitize user-supplied input in "cmnt_body" 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. Just enter a comment text like:
comment bit"><script>alert(document.cookie)</script>
in the "Dein Kommentar" textarea.