How to protect your CentOS server from the Shellshock exploit

Shellshock is quite a serious security hole found a couple of days ago in Bash; to check whether your CentOS server is vulnerable run the following in a terminal:
env VAR='() { :;}; echo Shellshock vulnerable!' bash -c "echo Bash Testing"
If your system is vulnerable, you will see:
Shellshock vulnerable! Bash testing
If it is not vulnerable, you will see:
bash: warning: VAR: ignoring function definition attempt bash: error importing function definition for `VAR’ Bash testing
If you are vulnerable, you can update bash by running the following:
sudo yum update bash
Once the update has finished, run the code to check your vulnerability again and it should be sorted.