Better a fix now than later, right? This particular flaw will not allow those with nefarious intentions to steal your personal data or credentials, it could still open some leeway for them to launch man-in-the-middle attacks which will eventually grant access to login pages on not only the router, but also on your computer as well.
For those who happen to be rocking to an older version of the AirPort, there is nothing much for you to worry about. This just goes to show that being an early adopter does not necessarily benefit you always. As for the other folks out there who happen to be making use of the latest networking devices from Apple, it would be highly recommended that you patch up your hardware without any further delay.