Selene is early-stage software. Installation, rollback, and complete removal modify Steam integration inside the current user's account. Artifact downloads write only to Selene's cache until the user confirms installation.

Do not publicly disclose exploitable details before a fix is available. Use GitHub private vulnerability reporting when it is available. Otherwise, open an issue requesting a private contact channel without including exploit details.

Include:

• affected version or commit;
• Linux distribution and architecture;
• native or Flatpak Steam;
• minimal reproduction steps;
• observed impact;
• logs with tokens, credentials, usernames, and personal data removed.

• Downloads must use HTTPS and cryptographic integrity checks.
• Archives must never escape their staging destination.
• Changes must be disclosed before confirmation.
• Mutations must remain in user scope.
• Backups must exist before replacement.
• Failures must trigger rollback whenever possible.
• Successful rollback must restart Steam.
• Selene must never read or store Steam credentials.

The current adapter runs setup.sh from the pinned slsteam-moon ZIP. It never executes the mutable LuaTools installer from the main branch. Before execution, Selene:

• verifies artifact size and SHA-256;
• rejects unsafe ZIP files and extracts into private staging;
• creates a persistent snapshot of every known destination;
• rejects root and requires initialized native Steam;
• removes inherited LD_* injection variables;
• sets SLSM_IMMUTABLE=1 and SLSM_SUDO_DENIED=1 to block system changes and administrative prompts.

Snapshots may contain copies of user settings. They are stored in private directories under XDG_STATE_HOME/selene/transactions and do not expire automatically yet.

Complete removal reuses the same pinned artifact, runs only its uninstall action without sudo, and creates a snapshot of the installed state first. Selene refuses to commit removal while a managed desktop tag, wrapper, runtime, or service remains. Games and Steam library files are outside the removal scope.

The downloader:

• accepts only HTTPS URLs from the embedded validated catalog;
• limits redirects and rejects HTTP downgrade;
• verifies declared size and SHA-256;
• writes into a restricted temporary file first;
• rejects path traversal, links, encrypted entries, duplicates, and excessive expansion;
• confirms required files before activating cache content.

The root install.sh installs only the Selene executable for the current user. It accepts Linux amd64, rejects root, enforces HTTPS redirects, requires the .sha256 asset, runs selene --version as a self-test, and atomically replaces the destination.

A checksum protects against corruption or isolated binary replacement, but it is not a signature and cannot protect against a compromised release account. Signed releases remain on the roadmap.