This is important if you're running a website too - this exploit can be used to take over the machine if the hacker finds a way to execute code as the website (

This is important if you're running a website too - this exploit can be used to take over the machine if the hacker finds a way to execute code as the website (i.e. once they used a different exploit to break in, they would be able to escalate from www-data user to root).