Admin/admin.php in phpBazar 2.1.0 and earlier allows remote attackers to bypass the authentication process and gain unauthorized access to the administrative section by setting the action parameter to edit_member and the value parameter to 1.
https://exchange.xforce.ibmcloud.com/vulnerabilities/26617
http://www.vupen.com/english/advisories/2006/1890
http://www.securityfocus.com/bid/18053
http://www.securityfocus.com/archive/1/434558/100/0/threaded