GHSA-9GM9-C8MQ-VQ7M

Vulnerability from github – Published: 2026-04-01 23:20 – Updated: 2026-04-06 22:53
VLAI?
Summary
PraisonAI: OS Command Injection in MCPHandler.parse_mcp_command()
Details

Summary

The --mcp CLI argument is passed directly to shlex.split() and forwarded through the call chain to anyio.open_process() 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)

# source
parts = shlex.split(command)

# hop
cmd, args, env = self.parse_mcp_command(command, env_vars)
self.server_params = StdioServerParameters(command=cmd, args=arguments)

# sink
process = await anyio.open_process([command, *args])

Fixed in commit 47bff65413beaa3c21bf633c1fae4e684348368c (v4.5.69) by introducing a command allowlist:

ALLOWED_COMMANDS = {"npx", "uvx", "node", "python"}
if cmd not in ALLOWED_COMMANDS:
    raise ValueError(f"Disallowed command: {cmd}")

PoC

# 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.

Severity ?
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Show details on source website
To clipboard 

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 4.5.68"
      },
      "package": {
        "ecosystem": "PyPI",
        "name": "praisonai"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.5.15"
            },
            {
              "fixed": "4.5.69"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-34935"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-78"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-01T23:20:00Z",
    "nvd_published_at": "2026-04-03T23:17:05Z",
    "severity": "CRITICAL"
  },
  "details": "### Summary\n\nThe `--mcp` CLI argument is passed directly to `shlex.split()` and forwarded through the call chain to `anyio.open_process()` with no validation, allowlist check, or sanitization at any hop, allowing arbitrary OS command execution as the process user.\n\n### Details\n\n`cli/features/mcp.py:61` (source) -\u003e `praisonaiagents/mcp/mcp.py:345` (hop) -\u003e `mcp/client/stdio/__init__.py:253` (sink)\n```python\n# source\nparts = shlex.split(command)\n\n# hop\ncmd, args, env = self.parse_mcp_command(command, env_vars)\nself.server_params = StdioServerParameters(command=cmd, args=arguments)\n\n# sink\nprocess = await anyio.open_process([command, *args])\n\n```\n\nFixed in commit `47bff65413beaa3c21bf633c1fae4e684348368c` (v4.5.69) by introducing a command allowlist:\n```python\nALLOWED_COMMANDS = {\"npx\", \"uvx\", \"node\", \"python\"}\nif cmd not in ALLOWED_COMMANDS:\n    raise ValueError(f\"Disallowed command: {cmd}\")\n```\n\n### PoC\n```python\n# tested on: praisonai==4.5.48\n# install: pip install praisonai==4.5.48\n# run: praisonai --mcp \"bash -c \u0027id \u003e /tmp/pwned\u0027\"\n# verify: cat /tmp/pwned\n# expected output: uid=1000(...) gid=1000(...) groups=1000(...)\n```\n\n### Impact\n\nAny 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.",
  "id": "GHSA-9gm9-c8mq-vq7m",
  "modified": "2026-04-06T22:53:58Z",
  "published": "2026-04-01T23:20:00Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/MervinPraison/PraisonAI/security/advisories/GHSA-9gm9-c8mq-vq7m"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-34935"
    },
    {
      "type": "WEB",
      "url": "https://github.com/MervinPraison/PraisonAI/commit/47bff65413beaa3c21bf633c1fae4e684348368c"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/MervinPraison/PraisonAI"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "PraisonAI: OS Command Injection in MCPHandler.parse_mcp_command()"
}


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