Launchpad.net

CVE 2009-3585

Session fixation vulnerability in html/Elements/SetupSessionCookie in Best Practical Solutions RT 3.0.0 through 3.6.9 and 3.8.x through 3.8.5 allows remote attackers to hijack web sessions by setting the session identifier via a manipulation that leverages a second web server within the same domain.

See the CVE page on Mitre.org for more details.