CVE-2026-79538
Deferred Deferred - Pending Action

Code Execution in MetaMCP via MCP Inspector Proxy

Publication date: 2026-09-29

Last updated on: 2026-09-29

Assigner: MITRE

Description
metatool-ai MetaMCP up to and including 2.4.22 is vulnerable to Code Execution in the internal MCP inspector proxy endpoint GET /mcp-proxy/server/stdio (createTransport, STDIO branch, routers/mcp-proxy/server.ts).

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Meta Information

Published
2026-09-29
Last Modified
2026-09-29
Generated
2026-10-19
AI Q&A
2026-09-29
EPSS Evaluated
2026-10-18
NVD
CVE-2026-79538
EUVD
EUVD-2026-89360

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
metatool-ai metamcp to 2.4.22 (inc)

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Exploitability

CWE
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KEV
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CWE ID Description
CWE-94 The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.

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Executive Summary

This vulnerability allows code execution through the internal MCP inspector proxy endpoint in MetaMCP versions up to 2.4.22. The issue occurs in the GET /mcp-proxy/server/stdio route, specifically in the createTransport function's STDIO branch.

Detection Guidance

The vulnerability affects the internal MCP inspector proxy endpoint in MetaMCP versions up to 2.4.22. To detect it, check if the endpoint GET /mcp-proxy/server/stdio is exposed and accessible on your network. Use network scanning tools like curl or wget to send a test request to the endpoint. For example, run: curl -v http://<target-ip>:<port>/mcp-proxy/server/stdio. If the endpoint responds, it may be vulnerable.

Impact Analysis

An attacker could exploit this to execute arbitrary code on systems running vulnerable versions of MetaMCP. This could lead to unauthorized access, data theft, or further compromise of affected systems.

Compliance Impact

The vulnerability allows remote code execution (RCE) with high impact (CVSS 9.8), which could lead to unauthorized access, data exfiltration, or system compromise. This poses significant risks to compliance with GDPR (data protection) and HIPAA (health data privacy) due to potential breaches of sensitive information.

Mitigation Strategies

Immediately upgrade metatool-ai MetaMCP to a version beyond 2.4.22 to address the code execution vulnerability in the MCP inspector proxy endpoint.

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