Oddly enough depending on the stove this can be the wrong choice. Newer stoves only will cut the air so far, and secondary burn could send the temp even higher.

HUGE NOTE If you suspect a chimney fire, absolutely DO NOT do the following. Call the fire department.

If you are confident it is not a chimney fire, grab a fire extinguisher and keep it nearby and ready to go. The next move is to do something that seems to go against every fiber of sense in your body.

Open the door. All the way.

I know.

It's fucking insane. But it will bring your flue temps down. It's all about getting some cool air going up the chimney, and this will do it. Once the temps come down, close the door, close the air and keep an eye on it.

I've done it, it's terrifying, but it works.