Please report security issues privately, not in public issues or pull requests. Use GitHub's private reporting: the repository's Security tab → Report a vulnerability (GitHub Security Advisories). Include the affected version/commit, reproduction steps, and the impact you observed.

We aim to acknowledge a report within a few days and will coordinate a fix and disclosure timeline with you.

Silo is pre-1.0. Security fixes target the latest released version and main; older versions are not maintained.

Silo's extension security model is documented and deliberate, so some things that look like holes are known design, not bugs:

• Extensions are trusted, in-process code. A third-party extension runs in the same process as the app and shares its privileges. Workspace path-scoping and the install-time capability consent (permissions guide, ADR 0015) provide honest-mistake containment, consent, and audit — not a sandbox. A determined hostile extension can bypass the ctx chokepoint entirely; this is a known limitation tracked in RFC 0006 (sandboxed execution). "An installed extension accessed files / the network" is therefore by design, not a reportable vulnerability — until the sandbox lands, the rule is install extensions you trust.

In scope (please do report): anything that lets content cross a boundary the docs claim is enforced — e.g. a path that escapes workspace scoping through ctx.files without the declared permission, a path-traversal in extension install, the dev automation bridge being reachable in a release build, or code execution from opening/previewing a file you didn't author.

When in doubt, report it privately — we would rather triage a non-issue than miss a real one.