A cash-out refinance can affect your credit score in several ways, though most of them are minor.
For one, applying for the loan will trigger a hard pull, which can result in a slight, temporary, drop in your credit score. Replacing your old mortgage with a new mortgage will also lower the average age of your credit accounts, which could potentially have a small, negative impact on your score.
However, if you use a cash-out refinance to pay off debt, you might see a boost to your credit score if your credit utilization ratio drops. Credit utilization, or how much you’re borrowing compared to what’s available to you, is a critical factor in your score.