Each lender and loan type has a different credit score requirement. VA loans are typically the most lenient as the Veterans Administration who backs the loans technically does not have a minimum score, but the lenders the VA works through to offer the loans typically do.  Lenders offering VA and FHA loans typically have options down to 580 and Conventional loans require at least a 620.
But remember, if your credit score is on the lower end, lenders will look more closely at your other financial details and this will likely lead to qualifying you at a lower amount, higher interest rate and payment options, and possibly requiring a larger down payment. This is why a 640 to 680 score is more commonly associated with what you need to buy a home.