This repository contains a Proof-of-Concept (PoC) automation script demonstrating CVE-2026-23744, a critical-severity vulnerability affecting @mcpjam/inspector (a local-first development platform for Model Context Protocol servers).

The vulnerability stems from Missing Authentication for a Critical Function (CWE-306) combined with an insecure default network binding. By default, the MCPJam Inspector interface binds to 0.0.0.0 rather than 127.0.0.1, exposing the HTTP API control plane to the local network or the internet. Remote threat actors can exploit the unauthenticated /api/mcp/connect endpoint by transmitting a crafted JSON payload containing arbitrary operating system commands inside the serverConfig object, leading to full-context Remote Code Execution (RCE).

Technical Flow

The automated assessment tool implements the following logical methodology:

1. Target Verification (ICMP Handshake): Evaluates host availability before initializing the network payload sequence to prevent socket errors or execution hanging.
2. Listener Initialization: Spawns a controlled handler to intercept the incoming reverse shell connection.
3. Payload Construction: Assembles a JSON configuration payload, embedding a dynamically base64-encoded callback string to avoid character escaping boundaries during remote parsing.
4. Exploitation Vector: Transmits an unauthenticated HTTP POST request to the target's exposed orchestration interface (/api/mcp/connect), forcing the application runtime to drop down to the shell layer and execute the payload.

Architecture Components

• exploit.py: The core automation framework handling host state checks, payload encoding, and HTTP interaction.
• Target Interface: /api/mcp/connect
• Impact: Full administrative access under the context of the user running the MCPJam Inspector process (typically a developer workstation, CI/CD runner, or build server).

Prerequisites & Usage

Ensure your environment is properly provisioned with Python 3.x before running the assessment framework.

Installation