Should I pay rent when the landlord has been foreclosed on and the house is pending sale to someone else?

Until your landlord is no longer the legal owner, you must continue to pay your rent. This is true whether or not your landlord continues to pay their mortgage. As for any security deposit, your current, not future, landlord is responsible for its return (considering the circumstances you may have to sue in small claims in an attempt to get it back). However, if the foreclosure has already taken place and ownership of the property has passed, then your rental obligation to this landlord has terminated. You now owe rent to the new landlord.

Note:  You should be aware that in the event of a foreclosure a tenant still has rights to occupancy. The “Protecting Tenants at Foreclosure Act” requires that when a home goes into foreclosure, tenants who have a written lease can continue to occupy the home until the end of the lease period, or 90 days, whichever is longer. The only exception would be if the new owner intends to move in and occupy the home as their primary residence. In that case, a 90 day notice to move would apply. Those tenants with a month-to-month lease, or no lease at all, have to be given at least 90 days notice to move. Additionally, in cases where state law provides more protection than the federal law, the state law applies.