Prevent modulescript from accessing or setting script's enviroment

Let’s say I have a script that requires custom user-made modulescripts, the module script returns a function, which is executed with a locked table that the module script uses to interface with the script, the function returns the module script’s function, which are Start and Stop, and they do different stuff depending on what the user does with the modulescript. How do I prevent the ModuleScript from getting or changing the enviroment of the script that required it?

I have also considered a sandbox, but that would be overkill.