When buying at public auction, properties are sold free and clear of all liens and encumbrances. The terms and conditions of the sale will tell you if there is anything you need to concerned with. The auction company will be able to tell you if there is anything you need to know.
At foreclosure auctions, it’s very important to read the legal advertisement to be certain what it is you are bidding on. If you are bidding on the first deed of trust, all junior liens, i.e. second mortgage are wiped out. If you are bidding on a second lien, the first lien remains in place and as the purchaser, you are responsible for that lien. It’s important you check with the attorney at the auction is you have any questions.