source: http://www.securityfocus.com/bid/27516/info

Multiple 2Wire routers are prone to an access-validation vulnerability because they fail to adequately authenticate users before performing certain actions.

Unauthenticated attackers can leverage this issue to change the password of arbitrary user accounts on the router. Successful attacks will completely compromise affected devices.

2Wire routers that have the 'H04_POST' page are affected by this issue.

UPDATE: This BID has been retired because it has been found to be a duplicate of BID 27246 (2Wire Routers Cross-Site Request Forgery Vulnerability).

UPDATE (February 1, 2008): This BID is being reinstated. Further investigation and new information reveal that this vulnerability differs from the one described in BID 27246. 

http://www.example.com/xslt?PAGE=H04_POST&PASSWORD=admin&PASSWORD_CONF=admin