TYPO3 Core

A FE user logs in, I set some session data that get's saved in
fe_sesson_data. Now the user logs out, another FE user logs in (same
browser, same machine, a second later).

This new user has the same session data as the one that just logged out. So
logoff() deletes the data from fe_sessions, but fe_session_data is only
cleaned with a 1% chance, not during logoff.

Obviously this needs to be changed, as session data should not persist.

http://typo3.org/documentation/mailing-lists/dev-list-archive/thread/110129500/
(issue imported from #M1252)