427BB 2.2 and 2.2.1 verifies authentication credentials based on the username, authenticated, and usertype cookies, which allows remote attackers to bypass authentication by using a valid username and usertype and setting the authenticated cookie.
https://exchange.xforce.ibmcloud.com/vulnerabilities/24038
http://www.vupen.com/english/advisories/2006/0091
http://www.securityfocus.com/archive/1/421326/100/0/threaded