CVE-2026-53328

A flaw was found in the Linux kernel's `sched_ext` component. When `systemd`'s user manager interacts with `subtree_control` while `sched_ext` is loaded, a warning can be triggered. This occurs due to a mismatch in how `cgroup` and `css` identities are handled during task migration, potentially leading to system instability or a local denial of service.