Selfhosted

If you are relying on Docker as a security boundary you are making a mistake.

Docker isolation is good enough to keep honest people honest but isn't good enough to keep out malicious actors. The Linux kernel API is simply too large of an attack surface to be highly secure.

If you want to run completely untrusted software you want a VM boundary at a very minimum. Ideally run it on completely separate hardware. There are few exceptions like browser isolation and gVisor which are strong software isolation without a VM but docker or any Linux container runner is not on that list. If the software has direct access to the host kernel it shouldn't be considered secure.

Note that this news are important, I only want to give some peace of mind to the many amateurs self-hosting out there ;) Don't panic. Think about how such attacker might gain access. There's always a practical difference between a vulnerability being there and how easily it is exploitable. Most CVEs are theoretical, and combining 4 of them would be even more difficult. From what I read, the vulnerability would be in the Dockerfile itself. Also, you need to weigh in the motivation such attacker would have. If you're an average netizen is different from a multi billion dollar company website. So, the attacker would need to meet all those conditions described in the CVEs and even in that case, they might escape the container only to find it was installed in rootless mode, so they just have access as regular user. But that's depending on how docker was installed.

Don't run docker, so far it has proven quite insecure, and that was by design at first because docker was created for development environments and not for deployment.

Later docker added better security, because they understood the value in deployment too. But many distro are still insecure by default and it takes both the effort of sysadmins and image developers to deploy securely docker containers.

I switched to Podman: no daemon, no socket, no root operations out of the box. And the transition is basically seamless too.