GHSA-h444-6j9x-p8vh

mv: symlinks expanded during cross-device move (resource exhaustion / data duplication)

When moving directories across filesystems, uutils `mv` dereferences symlinks inside the tree, copying their targets as real files/dirs instead of preserving the symlinks. GNU preserves symlinks by default. E.g. a `etc_link -> /etc` inside the source becomes a full copy of `/etc` at the destination. **Impact:** (1) resource exhaustion — a small tree can expand into a huge copy (time/disk DoS); (2) unintended duplication of sensitive paths referenced by symlink; (3) symlink-loop amplification causing deep recursion. Recommendation: in cross-device fallback, detect symlinks via `symlink_metadata()` and recreate with `read_link()`/`symlink()`; add loop detection. **Remediation:** Acknowledged by Canonical; fixed in commit 9654e4ab. --- _Reported by Zellic in the *uutils coreutils Program Security Assessment* (prepared for Canonical, Jan 20 2026), audited commit `3a07ffc5a9bd4c283e75afa548ba1f1957bad242`. Finding 3.63. Credit: Zellic._