X Factor Finalists Eaten Alive By Bed Bugs?

Sources close to the contestants tell TMZ, the unidentified singers in question were staying at the Grafton Hotel ... and when four of them woke up in the morning, they were covered in bites.

We're told the contestants did a little digging and claim they discovered the hotel had a massive bed bug infestation -- so they bailed asap, and notified "X Factor" producers ... who then dealt with the hotel and found new digs for the singers.