Exploit for Missing Authentication for Critical Function in Mcpjam Inspector CVE-2026-23744

## https://sploitus.com/exploit?id=18388716-B313-53EE-AC64-C942EFC5962F
# CVE-2026-23744 – MCPJam Inspector Unauthenticated Remote Code Execution (RCE)

## Description

- **Product**: MCPJam Inspector
- **Affected versions**: ≤ 1.4.2
- **Fixed version**: 1.4.3
- **Type**: Unauthenticated Remote Code Execution (RCE)
- **Attack vector**: Network
- **Authentication required**: No
- **User interaction required**: No
- **CVSS v3.1**: 9.8 (Critical)

**CVE-2026-23744** is a critical **unauthenticated Remote Code Exection (RCE)** vulnerability affecting **MCPJam Inspector ≤ 1.4.2**. The issue arises because the Inspector exposes a management endpoint (`/api/mcp/connect`) that accepts user-controlled MCP server configuration and can trigger process execution without adequate authentication or security restrictions. Affected versions listen on `0.0.0.0` (all interfaces) by default instead of localhost, making remote exploitation possible if the service is network-accessible.

## Technical Details

The vulnerability is associated with the following endpoint:
```http
POST /api/mcp/connect
```

The endpoint accepts a JSON object containing a server configuration, like:
```json
{
  "serverConfig": {
    "command": "",
    "args": [""],
    "env": {}
  },
  "serverId": ""
}
```

This supplied configuration is then used by MCPJam Inspector to create and manage a new MCP server process. As the endpoint lacks sufficient authentication and security controls, an attacker can submit arbitrary process definitions that are executed by the Inspector service.

Fundamentally, the vulnerability is a **Missing Authentication for Critical Function (CWE-306)** issue in which the application exposes functionality intended for trusted local users and makes it accessible over the network without adequate security checks.

## Root Cause

The vulnerability arises from two design flaws:
1. **Unauthenticated Access to Process Management**
  - The API allows users to define how MCP servers are launched.
  - Critical functionality is accessible without authentication.
  - User-controlled process parameters are trusted by the application without any further validation.
2. **Insecure Default Exposure**
  - MCPJam Inspector listens on `0.0.0.0` by default.
  - The management API is reachable from other systems on the network.
  - Attackers can remotely interact directly with process creation functionality.

The resulting attack path can be visualized as follows:
```
Attacker → /api/mcp/connect → Process Creation → Operating System
```

As the application directly interfaces with the operating system process creation, successful exploitation can result in arbitrary command execution within the security context of the MCPJam Inspector service.

## Usage

```shell
python3 exploit.py -t  -lhost  -lport 
```

- `-t` (or) `--target`: Target URL or target IP address.
- `-lhost` (or) `--local-host`: Public IP address for the reverse shell to connect back.
- `-lport` (or) `--local-port`: Port to be used for the reverse shell.

Before using this program, you must first start a listener on your local machine using Netcat.

To do that, use the following command:
```shell
nc -lvnp 
```

Then, run the above command to get a reverse shell on the target. 

## Impact

Successful exploitation may allow an attacker to:
- Execute arbitrary commands on the target host,
- Read or modify sensitive files,
- Install persistence mechanisms,
- Deploy additional malware or tooling,
- Pivot to other systems within the environment,
- Potentially achieve complete system compromise depending on service privileges.

The vulnerability has been assigned a **CVSS v3.1 score of 9.8 (Critical)** due to its network-based attack vector, lack of authentication, absence of user interaction, and high impact on confidentiality, integrity, and availability.

## Mitigation

Immediately upgrade to **MCPJam Inspector 1.4.3** or later. Addditional defensive measures include:
- Restricting access to the Inspector interface,
- Binding services to localhost wherever possible,
- Limiting exposure through firewall rules,
- Running the service with the minimum privileges required,
- Monitoring for unauthorized access attempts.

## Disclaimer

This PoC is solely for educational, defensive security research, and authorized security testing. It should only be used against systems with explicit permission. Unauthorized use against third-party systems may violate applicable laws and regulations. The owner of this repository is not reponsible for any damages caused by the use of this program.

## Sources
1. [MITRE CVE Record – CVE-2026-23744](https://vulners.com/cve/CVE-2026-23744)
2. [NIST National Vulnerability Database (NVD) – CVE-2026-23744](https://nvd.nist.gov/vuln/detail/CVE-2026-23744)
3. [GitHub Security Advisory (GHSA-232v-j27c-5pp6)](https://github.com/MCPJam/inspector/security/advisories/GHSA-232v-j27c-5pp6)
4. [CVE-2026-23744 – Vulnerability Lookup](https://db.gcve.eu/vuln/CVE-2026-23744)
5. [CVE-2026-23744: Critical RCE in MCPJam Inspector Targeting Developers – CrowdSec](https://www.crowdsec.net/vulntracking-report/cve-2026-23744)
6. [CVE-2026-23744: MCPJam Inspector RCE Vulnerability – SentinelOne](https://www.sentinelone.com/vulnerability-database/cve-2026-23744/)