Vulnerability ID: HTB22350
Reference: http://www.htbridge.ch/advisory/xss_in_microsoft_sharepoint_server_2007.html 
Product: Microsoft SharePoint Server 2007
Vendor: Microsoft Corporation
Vulnerable Version: 12.0.0.6421 and Probably Prior Versions
Vendor Notification: 12 April 2010 
Vulnerability Type: XSS (Сross Site Sсriрting)
Status: Not Fixed, Vendor Alerted, Awaiting Vendor Response
Risk level: Medium 
Credit: High-Tech Bridge SA (http://www.htbridge.ch/) 

Vulnerability Details:
User can execute arbitrary JavaScript code within the vulnerable application. 

The vulnerability exists due to failure in the "/_layouts/help.aspx" script to properly sanitize user-supplied input in "cid0" 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: 


http://host/_layouts/help.aspx?cid0=MS.WSS.manifest.xml%00%3Cscript%3Ealert%28%27XSS%27%29%3C/script%3E&tid=X