CVE-2026-25905 PUBLISHED

Lack of isolation in mcp-run-python leads to MCP server takeover

Assigner: JFROG
Reserved: 08.02.2026 Published: 09.02.2026 Updated: 09.02.2026

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.

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:L
CVSS Score: 5.8

Product Status

Package Collection https://pypi.org/project/pip
Package Name mcp-run-python
Versions
  • Version 0 is affected

References

Problem Types

  • CWE-653 Improper Isolation or Compartmentalization CWE