Rust on baking pans is not dangerous.
All the rust on the baking pans is just oxidized iron and it's not bad for your health.
Our bodies naturally contain iron so if you get a bit of that rust into the baked goods and eat it then there's nothing bad that will happen to you from baking in the rusty baking pan.
However the rust on the baking pans that gets into the baked goods may make the baked goods taste bad so you will want to remove the rust from the baking pans if possible.
To remove the rust from the baking pan sprinkle it with some baking soda and then mix some vinegar with the baking soda and then take a wire brush or steel wool and scrub the rust off the pan.
Baking pans usually rust because they are not allowed to dry properly before storing them so make sure to allow the baking pans to dry fully before storing them.