If it is under warranty, then I would contact the manufacturer. If it isn't, then you can try the following.
First, pen it up and clean out all dust, debris, etc. Make sure you carefully remove all from everywhere and make sure the vents have good airflow.
Next, look at replacing the thermal paste.
Should none of this work, then check that the fans are actually running/turning on. Depending on the device, are one or more of them not running, or not running correctly? If so then they may need to be replaced.
If you can't resolve it on your own, or don't feel comfortable doing the work yourself, then try a local tech.