The jrCookie function in includes/jamroom-misc.inc.php in JamRoom before 3.4.0 allows remote attackers to bypass authentication and gain administrative access via a boolean value within serialized data in a JMU_Cookie cookie.
https://exchange.xforce.ibmcloud.com/vulnerabilities/44048
http://www.securityfocus.com/archive/1/494820/100/0/threaded
http://www.jamroom.net/phpBB2/viewtopic.php?t=24454
http://www.jamroom.net/index.php?m=td_tracker&o=view&id=1178