Apple said last week that the vast majority of OS X users weren’t at risk of the Shellshock bash exploit; only advanced users who had manually configured advanced UNIX services may be at risk.
Regardless, Apple has released patches for OS X Mavericks, Lion, and Mountain Lion. The patch isn’t available through OS X automatic update yet. You have to manually download and install the patch for your respective version of OS X. Make sure you download the patch for your specific operating system.
If you’re running the public or developer versions of OS X Yosemite, there isn’t a patch available yet.
Shellshock bash patch
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