Session fixation vulnerability in Plogger allows remote attackers to hijack web sessions by setting the PHPSESSID parameter.
https://exchange.xforce.ibmcloud.com/vulnerabilities/33863
http://www.securityfocus.com/archive/1/466772/100/0/threaded
http://www.majorsecurity.de/index_2.php?major_rls=major_rls46