swarmail stores the mail, agent names and project paths of your coding-agent sessions in a SQLite database on your computer, and it sends none of it to anyone but the clients you allow (see PRIVACY.md). By default the server has no authentication: it accepts only local connections and rejects non-local Origin headers (only the /healthz status route skips that check), so any program running as you can read its data, and exposing its port to a network is unsupported. The one supported way to reach it from another machine is SWARMAIL_HOST (README): a second listener on one named address that answers every route except /healthz only with a bearer token. Whoever holds the token can read and send all mail and read the roster, project paths and file reservations, so treat the token file like an SSH key. The server accepts any one non-loopback address, public ones included, so choose an address on a private network you trust, such as a Tailscale address. The extra listener speaks plain HTTP, so the token and mail are unencrypted unless that network encrypts them.

Use GitHub's private vulnerability reporting: open the repository's Security tab and choose Report a vulnerability. Please do not open a public issue for a security problem.

Include the version, your operating system and the host you run it with (for example Claude Code or Codex), and steps that reproduce the problem. Report privately anything that lets a program on another computer or a web page reach the server without the bearer token. Whoever can connect to the server can read and send any session's mail, because a session's name selects its inbox and is not authentication. That means any program on your own computer for the loopback listener, and any holder of the token for the remote one. Report that as an ordinary issue or feature request.

Only the latest release gets fixes.