Blackboard Academic Suite 6.0 and earlier does not properly clear session information when de-authenticating a user who is idle, which allows subsequent users to log in as the previous user and gain privileges. NOTE: the vendor has disputed this issue, saying that "This is a customer specific issue related to their Kerberos authentication single sign-on application and not a vulnerability in the Blackboard product.
http://www.securityfocus.com/bid/16438
http://www.securityfocus.com/archive/1/423778/100/0/threaded
http://www.securityfocus.com/archive/1/423686/100/0/threaded
http://www.securityfocus.com/archive/1/423654/100/0/threaded