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._

Source published

6 Jul 2026 20:24:53 UTC

Source modified

6 Jul 2026 20:41:30 UTC

Observed here

24 Oct 2026 13:19:54 UTC

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GitHub Advisory Database · CC-BY-4.0

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:L

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