Forclosure Wipes Out Lease

When property is sold, any legal claims against it -- mortgages (unless they're paid off), easements, mechanic's liens for unpaid work, and yes, leases -- remain in effect.  The new owner takes them along with the property.  THat's why it's important to have a title search before handing over the money, to make sure one isn't buying problems or unexpected debts or liabilities.

A foreclosure, on the other hand, wipes out most other claims against property. (This varies somewhat from one state to another.)  In many states, only unpaid taxes (IRS claims or property taxes) would remain on the property when it is sold at foreclosure.  So there goes the tenant's claim to the rest of the lease.