Navigate to your router's IP, go to Console Settings, scroll to Advanced and un-check Remote Access:
https://i.imgur.com/RzXpT6Q.png
After doing that, you can't access your router remotely from The Cloud, (well, you can log in over the VPN, remote into a computer on-site, and access the router from that computer) but you're secure against a whole class of bugs and errors in Someone Else's Computer.