Apple recently announced that it would make a patch to combat the dreaded "Shellshock" vulnerability when it announced that the "vast majority" of Mac users are safe, and it just arrived. It's just for Mavericks, though. If you're using Yosesmite, you still might have cause to worry despite initial rumors that users of Apple's latest desktop OS were safe from attacks.
Shellshock affects the bash command shell in both OS X and Linux (which run on Unix), and it allows outside users to inject harmful code into vulnerable systems. That poses major problems for users of other systems, but OS X's tight design reportedly generally means that you weren't in danger unless you were working with advanced Unix on a Mac yourself.
"With OS X, systems are safe by default and not exposed to remote exploits of bash unless users configure advanced UNIX services," Apple said in a statement to iMore on Friday.
There's good news if you're on older systems, too, as Apple has prepared associated patches for OS X Lion and OS X Mountain Lion. As for Yosemite? There's no word as to whether there's even a patch in the works, but if there is, hopefully we'll see it in the next couple of days.