java/org/apache/catalina/authenticator/FormAuthenticator.java in the form authentication feature in Apache Tomcat 6.0.21 through 6.0.36 and 7.x before 7.0.33 does not properly handle the relationships between authentication requirements and sessions, which allows remote attackers to inject a request into a session by sending this request during completion of the login form, a variant of a session fixation attack.
http://www.ubuntu.com/usn/USN-1841-1
http://www.securityfocus.com/bid/64758
http://www.securityfocus.com/bid/59799
http://www.oracle.com/technetwork/topics/security/cpujan2014-1972949.html
http://www.oracle.com/technetwork/security-advisory/cpuoct2016-2881722.html
http://tomcat.apache.org/security-7.html
http://tomcat.apache.org/security-6.html
http://svn.apache.org/viewvc?view=revision&revision=1417891
http://svn.apache.org/viewvc?view=revision&revision=1408044
http://rhn.redhat.com/errata/RHSA-2013-1437.html
http://rhn.redhat.com/errata/RHSA-2013-0964.html
http://rhn.redhat.com/errata/RHSA-2013-0839.html
http://rhn.redhat.com/errata/RHSA-2013-0834.html
http://rhn.redhat.com/errata/RHSA-2013-0833.html
http://archives.neohapsis.com/archives/bugtraq/2013-05/0041.html