Omarchy: any user process could get root without a password

A security researcher discovered that the default Docker configuration in the Omarchy distribution allowed almost any program running in a user session to escalate privileges to root — with no password, no sudo, and not a single confirmation prompt. The issue was fixed in version 4.0.1, and the main advice for users is simple: update.

What it comes down to

By default, Omarchy added the user to the docker group. That makes it possible to run containers without sudo. But on Arch the Docker daemon runs as root and listens on the /var/run/docker.sock socket, and members of the docker group can talk to it. Docker itself warns outright: membership in this group is effectively equivalent to root privileges.

A process with access to the socket can ask the root daemon to launch a container, mount arbitrary parts of the host filesystem into it, and work with them as root. The demonstration is vivid: an ordinary user cannot read /etc/shadow directly, but the command docker run --rm -v /:/hostroot alpine cat /hostroot/etc/shadow happily prints its contents.

Why it's dangerous

Linux supplementary groups are inherited by child processes, so the vulnerability affected the entire session. The author walked the process tree below the user's systemd --user and found the docker group on nearly every one — meaning the whole machine could be compromised by any vulnerable component: a browser, an editor, an IDE, an npm script, a random development tool and, especially relevant, AI coding agents. Compromising an ordinary application instantly turned into a complete takeover of the system.

A separate complaint is that the setting was opt-out rather than opt-in: the insecure trade-off was applied to the default account even if the person never used Docker at all, and it was never explained. Meanwhile the documentation mentioned the group only in the context of being able to “run Docker without root” — a phrasing from which a reader is more likely to conclude they're getting a safe rootless mode than to grasp the actual state of affairs.

Context and response

The issue affected versions prior to 4.0.1, including the latest ISO from the 3.x branch. Judging by the commit history, membership in the docker group appeared back in June 2025 and was removed from the default configuration only in August 2026. The author reported the vulnerability privately and praised the speed of the project's response, calling it a healthy sign, but added that this is not the first security problem with Omarchy (whose creator is DHH) and that he does not yet trust its decision-making process.

As a takeaway, the researcher reminds us: developers are a valuable target, their machines are often stripped of protective barriers for the sake of convenience and accumulate access to various systems. And for those who don't want to hand over root for the sake of containers, he recommends Podman — a daemonless alternative where containers run as ordinary child processes in their own namespaces.

Source: Hacker News