If I use my mortgage deferrals in the CARE act, will it prevent me from buying another house later?

It could...as of now lenders/investors want to see a 12 month payment history. Though the Care act allows for no effect to credit score reports will have a notation of a modification or some statement reflecting the forbearance.

Yes, no, and maybe. If you go into forbearance, you are telling lenders you can't make your payment. Lenders don't like that. But, if you are no longer in forbearance, all back payments have been made, or you are in a back payment payment plan for at least three months, with those payments all being made, you should be fine for future loans. Learn more at https://joemetzler.com/covid19/