Some of you may have heard of the latest bash vulnerability (codenamed "Shellshock").
Bash has been patched, but you may need to update.
In most cases, you can update GNU/Linux distributions with the standard update tool (e.g. apt-get, yum, or the graphical equivalent).
For OS X, you currently need to install it separately, from http://support.apple.com/kb/DL1769?viewlocale=en_US&locale=en_US .
Matt Flaschen