Apple has reached out to clarify that most Mac OS X users are safe from the circulating bash bug exploit also known as "Shellshock."
"The vast majority of OS X users are not at risk to recently reported bash vulnerabilities. Bash, a UNIX command shell and language included in OS X, has a weakness that could allow unauthorized users to remotely gain control of vulnerable systems. With OS X, systems are safe by default and not exposed to remote exploits of bash unless users configure advanced UNIX services. We are working to quickly provide a software update for our advanced UNIX users.”
So there you have it, nothing to worry about unless you're deep into UNIX.