CVE-2026-25905 – Lack of isolation in mcp-run-python leads to MCP server takeover

CVE ID : CVE-2026-25905

Published : Feb. 9, 2026, 9:01 a.m. | 18 minutes ago

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.

Severity: 5.8 | MEDIUM

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