What’s Vulnerable › Vulnerabilities

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

• Severity: medium (CVSS 5.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-02-09 · updated 2026-06-17
• Weakness: CWE-653

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.

References

• https://research.jfrog.com/vulnerabilities/mcp-run-python-lack-of-isolation-mcp-takeover-jfsa-2026-001653030/

Get alerted when CVE-2026-25905 or the next vulnerability affects your stack