CVE-2026-35351: uutils coreutils doesn't preserve file ownership during moves across different filesystem boundaries

The mv utility in uutils coreutils fails to preserve file ownership during moves across different filesystem boundaries. The utility falls back to a copy-and-delete routine that creates the destination file using the caller’s UID/GID rather than the source’s metadata. This flaw breaks backups and migrations, causing files moved by a privileged user (e.g., root) to become root-owned unexpectedly, which can lead to information disclosure or restricted access for the intended owners.