Xbox controller constantly moving up

My Xbox one controller keeps making me look up. The right stick that lets you look around won’t stop looking up. Even if I’m not moving it. I will be sitting there minding my own business and suddenly I’ll be looking straight up. I don’t move the stick it just looks up. The stick is not stuck and when I look back down, it moves up again. Anyone know how to fix it? (Preferably without buying new parts)