Summary

The --mcp CLI argument is passed directly to shlex.split() and forwarded through the call chain to anyio.openprocess() with no validation, allowlist check, or sanitization at any hop, allowing arbitrary OS command execution as the process user.

Details

cli/features/mcp.py:61 (source) -> praisonaiagents/mcp/mcp.py:345 (hop) -> mcp/client/stdio/init.py:253 (sink) python source parts = shlex.split(command)

hop cmd, args, env = self.parsemcpcommand(command, envvars) self.serverparams = StdioServerParameters(command=cmd, args=arguments)

sink process = await anyio.openprocess([command, args])

Fixed in commit 47bff65413beaa3c21bf633c1fae4e684348368c (v4.5.69) by introducing a command allowlist: python ALLOWEDCOMMANDS = {"npx", "uvx", "node", "python"} if cmd not in ALLOWEDCOMMANDS: raise ValueError(f"Disallowed command: {cmd}")

PoC python tested on: praisonai==4.5.48 install: pip install praisonai==4.5.48 run: praisonai --mcp "bash -c 'id > /tmp/pwned'" verify: cat /tmp/pwned expected output: uid=1000(...) gid=1000(...) groups=1000(...)

Impact

Any deployment where the --mcp argument is influenced by untrusted input is exposed to full OS command execution as the process user. No authentication is required.