Avast wifi scanner - "device is accessible from the internet"

[louisclementharris]

Hi. My parents' computer has recently been showing an error when scanned. apparently their router is accessible from the internet now? They've been using it for a while and this error never came up before so I'm not sure what to do. They're not really interested in installing a VPN unless absolutely necessary. (I can post a screenshot of the error message with all of the specifics if necessary but I'm not sure if any of that is sensitive information?)

Thanks

[Pondus]

.    "device is accessible from the internet"

Does router have default admin name and log in password?