Chances are it's not. Check the forum for posts about it and look to see what's going on.
Click HERE to see the latest posts.

Click here to see if there's any news about it.

If it's a punkbuster game CLICK HERE to update the software manually and see if that's the problem.

Now, provided your hack is detected, what do you do?
It's simple! Follow these steps:

1. Remain calm. At the very worst you'll need to buy a new CD key for your game or a new steam account.You'll only need to do this if you were actually caught and GLOBALLY banned, not server banned. (To check, try joining a few different random servers)
2. Don't panic and post hatespeech about Mist, Sheep, Patrick or Maz. They're very likely busting their butts to turn out a solution. Quality takes time. 
3. Read, read read. Check the forums every few hours and see if a temporary "fix" is up. You'll notice a lot of flames from newbies but rest assured that most of the flamers will get banned. Don't become one of them.
4. Watch the Sheep. Sheep himself will post when a patch is released or when a new version of Mist is out. Read all of his posts carefully.
5. Wait for it...There's not a lot that the average member can do to hurry new development along aside from not PMing Sheep every 5 minutes for a fix request or a "How bout now" post. If you're lucky enough to be asked then you MAY be able to help in the testing. It's quite an honor and usually followed by much merriment and dancing around a fire. There's sometimes a virgin sacrifice, but it's only if one is available.

That's about it! The longest Mist has been without a quality hack for any particular highly desired game is 30 days, the shortest is 2 days. It may take a little patience but in the long run you'll be rewarded with another taste of n00b blood.
Until then have fun reading the crazy jokes, videos, and teasing on the forums. Hell, that's half the fun right there!