OpenClaw versions before 2026.3.28 contain an authorization bypass vulnerability in the chat.send gateway method. The vulnerability allows authenticated operator clients to spoof ACP identity labels and inject reserved provenance fields by manipulating client metadata during WebSocket connection handshake. ACP-only provenance fields are improperly gated by self-declared client metadata rather than verified authorization state. This enables privilege escalation where operators can impersonate ACP bridge identity and inject fields intended only for the ACP bridge component.