In keeping with it’s “one-a-month” trend for then year so far, Apple has released Security Update 2007-05.
According to the Apple notification it contains updates to the following components:
I applied the Universal version of the update to my iMac through software update without a problem. The update does require a reboot and on my iMac it did a bit of a double reboot. During the first reboot, which took longer than usual, another reboot was done. This occurred before the logon screen appeared. That second reboot took the normal length of time.
My PPC Mac Mini is currently packed away so I haven’t tried the PPC version of the update and it will be awhile before I do.