@grackle-ai/mcp has a workspace authorization bypass in its knowledge_search MCP tool
Date: 2026-03
Affected: npm/@grackle-ai/mcp
Attack vector: auth-bypass
Category: vulnerability-disclosure
Severity: High
CWE: CWE-284

### Impact The `knowledge_search` and `knowledge_get_node` MCP tools are included in `SCOPED_TOOLS` (visible to scoped agents) but their handlers do not receive `authContext` and do not enforce workspace scoping. A scoped agent in Workspace A can supply an arbitrary `workspaceId` parameter to search or retrieve knowledge graph nodes from Workspace B, bypassing workspace isolation boundaries. This is a **cross-workspace data leakage** vulnerability affecting any deployment where multiple workspaces contain sensitive knowledge graph data and scoped agents are used. **Affected code:** - `packages/mcp/src/tools/knowledge.ts:146-169` (knowledge_search handler) - `packages/mcp/src/tools/knowledge.ts:244-283` (knowledge_get_node handler) - `packages/mcp/src/tool-scoping.ts:11` (both tools listed in SCOPED_TOOLS) **Contrast with correct implementation:** `knowledge_create_node` (same file, lines 334-357) properly receives `authContext` and overrides the user-supplied `workspaceId` for scoped callers. ### Design Note Cross-workspace knowledge sharing is a legitimate future feature — agents working across different repos may need to collaborate and share knowledge. However, this access should be **opt-in with explicit grants**, not an implicit bypass. The immediate fix locks scoped agents to their own workspace. A future design could introduce: - Workspace-level "share knowledge with" settings - A `cross_workspace` scope on scoped tokens - Explicit `workspaceIds` (plural) in the


Mitigations:

Architectural layers (MAESTRO):