Fix Bash vulnerability under Linux OS .

If some Bash code outside of the curly brace then it will then be executed by the Linux system.

env x='() { :;}; echo vulnerable' bash -c " bash test "

1	env x='() { :;}; echo vulnerable' bash -c " bash test "

If your system is vulnerable, it will then output:

vulnerable
bash test

1 2	vulnerable bash test

How Do You Fix It?
Just open up a terminal and type:

sudo apt-get update
sudo apt-get upgrade

1 2	sudo apt-get update sudo apt-get upgrade

or under Fedora with :

sudo yum update

1	sudo yum update