GHSA-xq7h-vwjp-5vrh: 
JavaScript vulnerability analysis and mitigation

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