CVE-2026-23744: MCPJam inspector unauthenticated RCE via crafted HTTP request

Automated analysis

Generated by VULONE's analysis model from the NVD record, CISA KEV and EPSS data on 19 September 2026. Confidence: high.

critical priorityCVSS 9.8 with no authentication or user interaction required, default network exposure, and public exploit material make this an urgent patch.

What it is

MCPJam inspector versions 1.4.2 and earlier expose a critical function without authentication, allowing a crafted HTTP request to trigger installation of an MCP server and achieve remote code execution. Because the inspector listens on 0.0.0.0 by default rather than localhost, the flaw is reachable over the network, not just locally. Version 1.4.3 patches the issue.

Impact

An unauthenticated attacker gains remote code execution on the host running the inspector, with full compromise of confidentiality, integrity and availability.

Attack surface

Reachable over the network via a simple HTTP request to the inspector service, which binds to 0.0.0.0 by default. No authentication or user interaction is required per the CVSS vector (AV:N/AC:L/PR:N/UI:N).

Exploitation

Not listed in CISA KEV, but EPSS is 0.64842 (99.2nd percentile) and the vendor advisory reference is tagged Exploit, indicating public exploit material exists.

What to do

• Upgrade MCPJam inspector to version 1.4.3 or later.
• If immediate upgrade is not possible, bind the inspector to 127.0.0.1 and block external access to its port.
• Restrict network exposure of the inspector service with firewall rules or a reverse proxy requiring authentication.
• Run the inspector with least privilege and isolate it from production systems and sensitive credentials.
• Monitor for unexpected MCP server installations or child processes spawned by the inspector.

Detection

• Alert on HTTP requests to the inspector service that trigger MCP server installation endpoints.
• Monitor for unexpected child processes or package installations spawned by the inspector process.
• Audit network logs for external connections to the inspector port, especially from untrusted sources.
• Track MCP server configuration changes and new server registrations on hosts running the inspector.

This assessment is produced automatically and is not human-reviewed. Verify against the vendor advisory before acting on it.