Vulnerability ID: HTB22499
Reference: http://www.htbridge.ch/advisory/xss_vulnerability_in_amethyst.html 
Product: Amethyst
Vendor: Hulihan Applications ( http://hulihanapplications.com/projects/amethyst ) 
Vulnerable Version: 0.1.5 and Probably Prior Versions
Vendor Notification: 22 July 2010 
Vulnerability Type: Stored XSS (Cross Site Scripting)
Status: Fixed by Vendor
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 /browse/create_comment script to properly sanitize user-supplied input in "comment[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. Simple enter a string like 'mynameis' in "Your Name" field of post commenting form, text of comment (like You have some mistakes in your post), fill Captcha and press "Add Comment!" button. Alert will appear when the Administrator will edit the post.

Solution: Upgrade to the most recent version