

If that is indeed true it would only mean that the docker container is vulnerable to a supply chain attack. You are not any more vulnerable to a vulnerability in the codebase.
If you’re using the ghcr image, to post malicious code there, the attack would have already had to compromise their github infra … which would likely result in the attacker being able to push malicious code to git or publish malicious releases. Their linux distro packages are self published via a ppa/install script, which I would assume just pull from their github releases, so a bad github release would immediately be pulled as an update by users just as fast as a container.
GitHub lets you use them as an oauth provider. Issue solved.
Instance fragmentation is annoying in the sense while you can unify log in with oauth you can’t share settings between instances of the same software. Would be cool if oauth could have a generic user_data field to store json of settings maybe…