A flaw was found in Podman's auto-update functionality in versions 1.8.2 through 6.1.4. Podman copies image labels into containers, and auto-update trusts the io.containers.autoupdate and PODMAN_SYSTEMD_UNIT labels to determine whether a container should be updated and which systemd unit to restart. An attacker can supply a container image with crafted labels that, when run by a user and subsequently processed by auto-update, causes arbitrary systemd units to be restarted with that user's privileges. When Podman runs as root, targeting poweroff.target may shut down the host, resulting in a complete loss of availability.