CVE-2026-25905 — MEDIUM (5.8)

Vulnerability 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.

CVSS Score

5.8

MEDIUM

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

Attack Vector

NETWORK

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction

REQUIRED

Scope

CHANGED

Confidentiality

LOW

Integrity

LOW

Availability

LOW

Related Weaknesses (CWE)

CWE-653

References

https://research.jfrog.com/vulnerabilities/mcp-run-python-lack-of-isolation-mcp-

FAQ

What is CVE-2026-25905?

CVE-2026-25905 is a vulnerability with a CVSS score of 5.8 (MEDIUM). 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 resul...

How severe is CVE-2026-25905?

CVE-2026-25905 has been rated MEDIUM with a CVSS base score of 5.8/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-25905?

Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.