Ok, son is away, what do I do?? I am up to 10.4
First of all, there is nothing to worry about.
There is no malicious malware out in the wild. This was merely a proof of concept that showed a computer cracker COULD, if he were sitting at your machine, force the computer to execute a malicious application HE had already placed on your computer (because he was sitting at your machine and knows your administrator user name and password) by overflowing the stack and inserting an order to jump to the start of the software he had installed. I think it would be easier to merely double click on the installed app... since, after all, he IS sitting right at your keyboard and has your mouse in hand.
Secondly, if you do not know your son's administrator password for the computer, you will have to wait for him to come home.
If you do know them, and he has given you permission to upgrade, then simply click on the blue Apple on the menu bar and select "Software Update" and let the computer upgrade itself. You will have to put in the Administrator name and password when asked. It will update you to 10.4.7 and close the loophole. Just follow the prompts.