A flaw was found in bootc when operating with the default containers signature policy. Automatic or manual upgrades of a mutable image tag may apply unsigned content for registries that fall through to insecureAcceptAnything, allowing an attacker who can update that tag to execute arbitrary OS content as the host root filesystem on reboot.
Pin bootc updates to image digests, or configure /etc/containers/policy.json to reject unsigned content by default and allow only explicitly trusted signed scopes. Until policy is hardened, disable automatic updates (bootc-fetch-apply-updates.timer). After a suspected malicious image, do not rely on bootc rollback alone: audit and remediate persistent /var (including /var/roothome), then re-enroll to a trusted signed image.