Thank you for posting this... I often ignore doing updates because they're just not as interesting as other things I'm doing. This kicked my butt into gear to install the updates.
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).