Name :  XSS vulnerability in Joomla.
Software :  All 1.5.x installs prior to and including 1.5.19 are affected.
Vendor Hompeage :
Vulnerability Type :  Cross-Site Scripting
CVE :  CVE-2010-2535
Severity :  High
Researcher :  Mesut Timur <mesut [at] mavitunasecurity [dot] com>
Advisory Reference :  NS-11-001

Joomla is an award-winning content management system (CMS), which enables you to build Web sites and powerful online applications. Many aspects, including its ease-of-use and extensibility, have made Joomla the most popular Web site software available. Best of all, Joomla is an open source solution that is freely available to everyone.

Joomla is affected by a XSS vulnerability in various administrator screens. All 1.5.x installs prior to and including 1.5.19 are affected.
You can read the full article about Cross-Site Scripting vulnerabilities from here : /blog/web-security/cross-site-scripting-xss/

Upgrade to the latest Joomla! version (1.5.20 or later).

It has been discovered on testing of Netsparker, Web Application Security Scanner - /netsparker/.

1. Vendor URL :
2. MSL Advisory Link : /xss-vulnerability-in-joomla/
3. Netsparker Advisories : /web-applications-advisories/

About Netsparker
Netsparker® can find and report security issues such as SQL Injection and Cross-site Scripting (XSS) in all web applications regardless of the platform and the technology they are built on.  Netsparker's unique detection and exploitation techniques allows it to be dead accurate in reporting hence it's the first and the only False Positive Free web application security scanner.