Jetty before 4.2.27, 5.1 before 5.1.12, 6.0 before 6.0.2, and 6.1 before 6.1.0pre3 generates predictable session identifiers using java.util.random, which makes it easier for remote attackers to guess a session identifier through brute force attacks, bypass authentication requirements, and possibly conduct cross-site request forgery attacks.
https://exchange.xforce.ibmcloud.com/vulnerabilities/32240
http://www.vupen.com/english/advisories/2007/0497
http://www.securityfocus.com/bid/22405
http://www.securityfocus.com/archive/1/459164/100/0/threaded
http://secunia.com/advisories/24070
http://fisheye.codehaus.org/changelog/jetty/?cs=1274
http://archives.neohapsis.com/archives/bugtraq/2007-02/0070.html