Do you have that problem? That your code/art is accessible to the wider world when it shouldnt be? In that case it sounds more like a task for somebody with a security background then for someone with knowledge of copyright.
What I am trying to assess, though, is the fact that "there's something that is not yours and the owner decides if you can have/copy/ML it". Not the fact that someone did. Or, if did, what would the consequences be.
Trying to skip over the admin to fix this missconfiguration and going straight to the lawyer is the attempt to externalize costs. Which is where the lack of compassion comes in. This is a shitty thing to do.
This is not a lawyer problem, nobody broke in, nobody took anything. You are giving stuff away. Go talk to an admin on how to only give your toaster to the people that you want to give it to.