@grackle-ai/powerline Runs Without Authentication by Default
Date: 2026-03
Affected: npm/@grackle-ai/powerline
Attack vector: auth-bypass
Category: vulnerability-disclosure
Severity: Medium
CWE: CWE-306

### Impact When `--token` is not provided and `GRACKLE_POWERLINE_TOKEN` is not set, the PowerLine gRPC server runs with **zero authentication**. A warning is logged (`"NO AUTH (development only)"`) but nothing prevents deployment in this state. Any client that can reach the PowerLine port can spawn agent sessions, access credential tokens, and execute code. The default binding is `127.0.0.1` (loopback only), which limits exposure to the local machine. However, if PowerLine is accidentally exposed on a network (e.g., in a container or via port forwarding), the impact is critical. **Affected code:** - `packages/powerline/src/index.ts:46` — token defaults to empty string - `packages/powerline/src/index.ts:63-76` — auth interceptor is only added when token is truthy ### Patches 0.70.1 **Fix:** Require an explicit `--no-auth` flag to run without authentication, rather than defaulting to no auth when the token is empty. Throw an error if starting without a token and without `--no-auth`. ### Workarounds Always provide `--token` or set `GRACKLE_POWERLINE_TOKEN` when starting PowerLine. The Grackle server does this automatically when managing PowerLine lifecycle. ### Resources - CWE-306: Missing Authentication for Critical Function - File: `packages/powerline/src/index.ts`


Mitigations:

Architectural layers (MAESTRO):