JRun 4.0 does not properly generate and handle the JSESSIONID, which allows remote attackers to perform a session fixation attack and hijack a user's HTTP session.
https://exchange.xforce.ibmcloud.com/vulnerabilities/17481
http://www.securityfocus.com/bid/11245
http://www.macromedia.com/devnet/security/security_zone/mpsb04-08.html
http://www.kb.cert.org/vuls/id/584958