CVE-2026-25905: medium-severity vulnerability in mcp-run-python
Lack of isolation in mcp-run-python leads to MCP server takeover
Published
13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 5.8epss 0.2%
exploitation probability
0.2%top 86% of all CVEs
observed exploitation
nono source reports it
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:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:L
Affected products
mcp-run-pythonRelated CVEs — mcp-run-python
In the same product, most dangerous first.