Cooking too long, or too hot?
It's definitely a sign that the oven is cooking too hot somewhere; the under-done tops and middles are the give-away. I suspect your oven has a malfunctioning thermostat, which is quite common.   Try setting temperatures 50 degrees below suggested, and see if it solves the problems.  Failing this, purchase an oven thermometer to check it.

Another possibility is that there is poor airflow within the oven. In this case, hot air is heating the bottom of the pan, but cannot get around the edges of the pan to heat the top of the baked good.  The solution to this is usually to use a smaller pan, and ensure only one pan at a time is loaded into the oven.  My oven has problems of this nature when I try to bake in both racks with half sheet pans.