Piper runs on hardware you own and exposes it to the public internet — the agent terminates TLS, the relay carries traffic for boxes it doesn't control, and the CLI holds credentials for both. Security reports are welcome and taken seriously.

Piper is pre-1.0 and moves fast. Only the latest release receives security fixes; there are no backports to older tags. A fix ships in the next release cut from main.

Piper is self-hosted software, not a service we operate: there is no fleet-wide push, so applying a fix means upgrading your own box.

Please don't open a public issue for a suspected vulnerability.

Report it privately with GitHub's Report a vulnerability form — also reachable from this repo's Security tab. That opens a draft advisory visible only to you and the maintainers.

Helpful to include:

• what an attacker gains, and what access they need to start
• affected version and component (piperd, piper, piper-relay, packaging)
• steps to reproduce, or a proof of concept
• whether you're reporting something you observed or something you inferred from reading the code — both are welcome, just say which

Piper is maintained by a very small team. Expect an acknowledgement within a few days rather than the same hour; if you hear nothing after a week, please ping the advisory thread.

In scope — the three binaries and how they're delivered:

• piperd: the authenticated control API (the relay path and non-loopback binds), deploy orchestration, container and secret handling, certificate and TLS handling
• piper-relay: tenant isolation, enrollment and token handling, the tunnel protocol, SNI routing
• piper: credential storage and handling on the developer's machine
• the GitHub webhook path and PR-preview routing
• install.sh, the apt/Homebrew packaging, and the published container images

Out of scope:

• vulnerabilities in the applications you deploy on Piper — Piper builds and runs your code as given, and the security of that code is yours
• flaws in third-party dependencies with no Piper-specific exploit path; report those upstream (tell us anyway if Piper's use of them makes it exploitable)
• the loopback control API listener answering local requests without a token — that's deliberate (#221): the bind is the trust boundary, so anyone who can already run processes on the box is inside it. A way to reach that listener from off-box, or from a context that shouldn't have it, very much is in scope
• attacks that require an adversary who already has root on the box, or who already holds a valid agent or relay token
• findings from automated scanners with no demonstrated impact

We'll work with you on a fix and coordinate timing on disclosure, publishing a GitHub advisory once a release carrying the fix is out. Reporters are credited in the advisory unless you'd rather stay anonymous — just say so.