apfs-dedupe runs as root and rewrites files in place across user home directories, so its safety properties are part of its security surface. The apply is symlink-safe and anchored to a directory file descriptor, content is re-verified against a frozen clone immediately before each atomic swap, and a crash leaves the original file untouched. The README "Safety" section and docs/architecture.md document the full threat model.

This is a pre-1.0 project: fixes land on main and in the latest tagged release. There are no maintained older release branches.

Report security issues privately - do not open a public issue. Use GitHub's private vulnerability reporting: open the repository's Security tab and choose "Report a vulnerability", which opens a private advisory visible only to the maintainers.

Helpful details to include:

• macOS version (sw_vers -productVersion) and Apple silicon vs Intel
• The exact command, including whether it ran with --apply and as root
• What you observed versus expected
• A minimal reproduction, if you have one

This is a small project, so responses are best-effort rather than on a fixed SLA; we will acknowledge and work toward a fix as soon as we reasonably can.

In scope: path resolution and symlink handling during the apply, privilege boundaries when running as root over multi-user trees, metadata/ACL fidelity, and the scheduled LaunchAgent/LaunchDaemon install. The --system daemon's use of install-time tool paths is a documented limitation (README "Schedule a daily run"), not a separate vulnerability.