New security updates for Exchange 2007, 2010 and 2013 were released yesterday. However, the update for Exchange 2013 was withdrawn today due to problems. Unfortunately, this seems to be happening more frequently recently. If you have already installed the update for Exchange 2013, you can find a workaround to fix the problems here:
http://support.microsoft.com/kb/2879739
I'll probably wait a little longer until I install the updates...
If you can't or don't want to wait, you can find the packages here:
Das Update für den 2013 sollte man erst einmal lassen sonst geht die Suche innerhalb des Exchange nicht mehr.
PS: Ich hasse die Autoupdate-Funktion :|