The Python code being run by 'runPython' or 'runPythonAsync' is not isolated from the rest of the JS code, allowing any Python code to use the Pyodide APIs to modify the JS environment. This may result in an attacker hijacking the MCP server - for malicious purposes including MCP tool shadowing. Note - the "mcp-run-python" project is archived and unlikely to receive a fix.
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Fixes

Solution

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Workaround

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History

Mon, 09 Feb 2026 09:15:00 +0000

Type Values Removed Values Added
Description The Python code being run by 'runPython' or 'runPythonAsync' is not isolated from the rest of the JS code, allowing any Python code to use the Pyodide APIs to modify the JS environment. This may result in an attacker hijacking the MCP server - for malicious purposes including MCP tool shadowing. Note - the "mcp-run-python" project is archived and unlikely to receive a fix.
Title Lack of isolation in mcp-run-python leads to MCP server takeover
Weaknesses CWE-653
References
Metrics cvssV3_1

{'score': 5.8, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:L'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: JFROG

Published:

Updated: 2026-02-09T09:01:16.728Z

Reserved: 2026-02-08T11:19:42.865Z

Link: CVE-2026-25905

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-02-09T09:16:34.030

Modified: 2026-02-09T09:16:34.030

Link: CVE-2026-25905

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses