index2.php in Mambo 4.0.12 allows remote attackers to gain administrator access via a URL request where session_id is set to the MD5 hash of a session cookie.
https://exchange.xforce.ibmcloud.com/vulnerabilities/11398
https://euvd.enisa.europa.eu/vulnerability/EUVD-2003-1235
http://www.securityfocus.com/bid/6926
http://archives.neohapsis.com/archives/bugtraq/2003-02/0302.html