I have an old refrigerator that is too cold. The freezer works fine, but The fridge freezes everything solid and all water condensate freezes on sides. I've turned the thermostat to warmest setting. No change.

Bad thermostat not telling it when to shut off?

Bad stat is a good guess. I'd defrost the entire refrigerator and allow it to reach room temps for several hours. Now restart the frig and see if it is any better. Some older units tend to build up ice which can block the air circulation. This could alos be a bad defrost heater element.