Email security@capabilityhostprotocol.com with a description, reproduction steps, and the affected version. Please do not open a public issue for undisclosed vulnerabilities. We aim to acknowledge reports within 72 hours.

Signed evidence, identity, provenance, mandate, and witnessing verification are the protocol's security core — reports against packages/python/chp_core/signing.py, the canonicalization (chp-stable-v1), or the conformance suite's guarantees are especially valuable.

All protocol changes are additive (spec/CHANGELOG.md documents every version's regression gate), so upgrading within the 0.x line does not break wire compatibility.

• Security model (normative, current): spec/chp-security-model.md — the guarantee × adversary × residual-risk matrix
• Threat model (v0.1, superseded): docs/security/threat-model-v0.1.md
• Production hardening & operations: docs/production-runbook.md
• Key compromise recovery: rotation (spec §3.2) → key revocation → re-anchor → mandate revocation (spec §10) — the runbook has the step-by-step.