PT-2026-30398 · Npm · @Grackle-Ai/Server

Published

2026-03-25

·

Updated

2026-03-25

CVSS v4.0

7.1

High

VectorAV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Impact

The WebSocket upgrade handler in the server validates authentication (API key token or session cookie) but does not check the Origin header. A malicious webpage on a different origin could initiate a WebSocket connection to ws://localhost:3000/ws if it can leverage the user's session cookie (which is SameSite=Lax, allowing top-level navigations).
This enables cross-origin WebSocket hijacking — if a user visits a malicious site while a Grackle session is active, the attacker's page could open a WebSocket and subscribe to real-time events (session output, task updates, environment state).
Affected code:
  • packages/server/src/ws-bridge.ts:80-91 — connection handler accepts WebSocket upgrades without checking req.headers.origin

Patches

Fix: Validate req.headers.origin against an allowlist before accepting connections:
typescript
const origin = req.headers.origin || "";
if (origin && !origin.includes("localhost") && !origin.includes("127.0.0.1")) {
 ws.close(4003, "Invalid origin");
 return;
}

Workarounds

Ensure the Grackle server is only accessible on 127.0.0.1 (the default). Do not use --allow-network in untrusted network environments.

Resources

  • CWE-346: Origin Validation Error
  • File: packages/server/src/ws-bridge.ts

Fix

Origin Validation Error

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Weakness Enumeration

CWE-346

Related Identifiers

GHSA-W3HV-X4FP-6H6J

Affected Products

@Grackle-Ai/Server