Screenhand MCP Server

In the server's implementation (`dist/mcp-desktop.js:3595`): Evaluating a runtime value as code (rather than a fixed literal) executes whatever reaches it — a direct RCE primitive, and almost never necessary in legitimate code. This is read from the code itself — not from the tool description — so a poisoned server cannot hide it behind honest-looking metadata.

Evidence: // dynamic AppleScript eval (can construct blocked commands) /do\s+script/i, // Terminal.app shell execution

Fix: Review this call path: confirm it never receives unsanitized tool input, constrain it, or remove it. Treat a server whose code reaches these sinks as high-capability regardless of what its tools claim.

Location: server dist/mcp-desktop.js

The implementation both builds shell commands out of runtime values (`dist/mcp-desktop.js`) and evaluates runtime values as code (`dist/mcp-desktop.js`). Each is a separate arbitrary-execution primitive; a server exposing both gives anything that reaches either one a direct path to running attacker-chosen code.

Fix: Remove the dynamic eval, and pass command arguments as an argv array instead of building a shell string. If both are genuinely required, constrain and validate every value that can reach them.

Location: server dist/mcp-desktop.js

In the server's implementation (`dist/mcp-desktop.js:3595`): Evaluating strings as code is the most direct RCE primitive; if any tool input reaches it, the server executes attacker-chosen code. This is read from the code itself — not from the tool description — so a poisoned server cannot hide it behind honest-looking metadata.

Evidence: // dynamic AppleScript eval (can construct blocked commands) /do\s+script/i, // Terminal.app shell execution

Fix: Review this call path: confirm it never receives unsanitized tool input, constrain it, or remove it. Treat a server whose code reaches these sinks as high-capability regardless of what its tools claim.

Location: server dist/mcp-desktop.js

In the server's implementation (`dist/mcp-desktop.js:37`): Spawning a shell/process is command-execution capability; with unsanitized tool input it is command injection / RCE. This is read from the code itself — not from the tool description — so a poisoned server cannot hide it behind honest-looking metadata.

Evidence: Sync, exec } from "node:child_process"; import { promisify } from "node:util"; const execAsync = promisify(exec); import

Fix: Review this call path: confirm it never receives unsanitized tool input, constrain it, or remove it. Treat a server whose code reaches these sinks as high-capability regardless of what its tools claim.

Location: server dist/mcp-desktop.js

In the server's implementation (`dist/src/jobs/runner.js:587`): Spawning a shell/process is command-execution capability; with unsanitized tool input it is command injection / RCE. This is read from the code itself — not from the tool description — so a poisoned server cannot hide it behind honest-looking metadata.

Evidence: } = await import("node:child_process"); execSync(`open ${JSON.stringify(url)}`, { timeout: 10_000 });

Fix: Review this call path: confirm it never receives unsanitized tool input, constrain it, or remove it. Treat a server whose code reaches these sinks as high-capability regardless of what its tools claim.

Location: server dist/src/jobs/runner.js

In the server's implementation (`dist/src/native/bridge-client.js:17`): Spawning a shell/process is command-execution capability; with unsanitized tool input it is command injection / RCE. This is read from the code itself — not from the tool description — so a poisoned server cannot hide it behind honest-looking metadata.

Evidence: rt { spawn } from "node:child_process"; import { EventEmitter } from "node:events"; import fs from "node:fs"; import pat

Fix: Review this call path: confirm it never receives unsanitized tool input, constrain it, or remove it. Treat a server whose code reaches these sinks as high-capability regardless of what its tools claim.

Location: server dist/src/native/bridge-client.js

In the server's implementation (`dist/src/runtime/applescript-adapter.js:17`): Spawning a shell/process is command-execution capability; with unsanitized tool input it is command injection / RCE. This is read from the code itself — not from the tool description — so a poisoned server cannot hide it behind honest-looking metadata.

Evidence: { execFile } from "node:child_process"; import { randomUUID } from "node:crypto"; import { promisify } from "node:util";

Fix: Review this call path: confirm it never receives unsanitized tool input, constrain it, or remove it. Treat a server whose code reaches these sinks as high-capability regardless of what its tools claim.

Location: server dist/src/runtime/applescript-adapter.js

In the server's implementation (`dist/src/test-mcp-protocol.js:17`): Spawning a shell/process is command-execution capability; with unsanitized tool input it is command injection / RCE. This is read from the code itself — not from the tool description — so a poisoned server cannot hide it behind honest-looking metadata.

Evidence: rt { spawn } from "node:child_process"; import { createInterface } from "node:readline"; import path from "node:path"; i

Fix: Review this call path: confirm it never receives unsanitized tool input, constrain it, or remove it. Treat a server whose code reaches these sinks as high-capability regardless of what its tools claim.

Location: server dist/src/test-mcp-protocol.js

In the server's implementation (`dist/src/util/sanitize.js:7`): Spawning a shell/process is command-execution capability; with unsanitized tool input it is command injection / RCE. This is read from the code itself — not from the tool description — so a poisoned server cannot hide it behind honest-looking metadata.

Evidence: { execSync } from "node:child_process"; import os from "node:os"; const MAX_STRING_LENGTH = 1000; const ALLOWED_URL_PROT

Fix: Review this call path: confirm it never receives unsanitized tool input, constrain it, or remove it. Treat a server whose code reaches these sinks as high-capability regardless of what its tools claim.

Location: server dist/src/util/sanitize.js

Untrusted-input tools ([platform_learn]) co-exist with external-action tools ([applescript]). A prompt injection could cause unwanted external actions, though no direct sensitive-data leak path was found.

Evidence: untrusted [platform_learn] → sinks [applescript]

Fix: Require confirmation for state-changing/egress actions triggered after processing untrusted content.

Location: flow platform_learn → applescript

In the server's implementation (`dist/src/memory/research.js:60`): A hardcoded outbound call to a fixed external host inside server code is a classic exfiltration/telemetry channel — especially paired with reads of local data. This is read from the code itself — not from the tool description — so a poisoned server cannot hide it behind honest-looking metadata.

Evidence: const response = await fetch("https://api.anthropic.com/v1/messages", { method: "POST", headers

Fix: Review this call path: confirm it never receives unsanitized tool input, constrain it, or remove it. Treat a server whose code reaches these sinks as high-capability regardless of what its tools claim.

Location: server dist/src/memory/research.js

In the server's implementation (`dist/src/planner/planner.js:967`): A hardcoded outbound call to a fixed external host inside server code is a classic exfiltration/telemetry channel — especially paired with reads of local data. This is read from the code itself — not from the tool description — so a poisoned server cannot hide it behind honest-looking metadata.

Evidence: const response = await fetch("https://api.anthropic.com/v1/messages", { method: "POST",

Fix: Review this call path: confirm it never receives unsanitized tool input, constrain it, or remove it. Treat a server whose code reaches these sinks as high-capability regardless of what its tools claim.

Location: server dist/src/planner/planner.js

In the server's implementation (`dist/src/state/visual-mapper.js:124`): A hardcoded outbound call to a fixed external host inside server code is a classic exfiltration/telemetry channel — especially paired with reads of local data. This is read from the code itself — not from the tool description — so a poisoned server cannot hide it behind honest-looking metadata.

Evidence: const resp = await fetch("https://api.anthropic.com/v1/messages", { method: "POST", headers

Fix: Review this call path: confirm it never receives unsanitized tool input, constrain it, or remove it. Treat a server whose code reaches these sinks as high-capability regardless of what its tools claim.

Location: server dist/src/state/visual-mapper.js

In the server's implementation (`dist/mcp-desktop.js:3612`): A shell/process command assembled from concatenated or interpolated values is command injection when any part is attacker-influenced — the OWASP canonical RCE flow. Verify what reaches the interpolated value. This is read from the code itself — not from the tool description — so a poisoned server cannot hide it behind honest-looking metadata.

Evidence: const result = execSync(`osascript -e '${script.replace(/'/g, "'\\''")}'`, { encoding: "utf-8",

Fix: Review this call path: confirm it never receives unsanitized tool input, constrain it, or remove it. Treat a server whose code reaches these sinks as high-capability regardless of what its tools claim.

Location: server dist/mcp-desktop.js

In the server's implementation (`dist/src/jobs/runner.js:588`): A shell/process command assembled from concatenated or interpolated values is command injection when any part is attacker-influenced — the OWASP canonical RCE flow. Verify what reaches the interpolated value. This is read from the code itself — not from the tool description — so a poisoned server cannot hide it behind honest-looking metadata.

Evidence: _process"); execSync(`open ${JSON.stringify(url)}`, { timeout: 10_000 }); return { ok: true, met

Fix: Review this call path: confirm it never receives unsanitized tool input, constrain it, or remove it. Treat a server whose code reaches these sinks as high-capability regardless of what its tools claim.

Location: server dist/src/jobs/runner.js

In a packaging/dev/install script (shipped, but not the server runtime) (`dist/scripts/supervisor-daemon.js:127`): Spawning a shell/process is command-execution capability; with unsanitized tool input it is command injection / RCE. This is read from the code itself — not from the tool description — so a poisoned server cannot hide it behind honest-looking metadata.

Evidence: } = await import("node:child_process"); const msg = recovery.instruction.replace(/"/g, '\\"');

Fix: Review this call path: confirm it never receives unsanitized tool input, constrain it, or remove it. Treat a server whose code reaches these sinks as high-capability regardless of what its tools claim.

Location: server dist/scripts/supervisor-daemon.js

In a packaging/dev/install script (shipped, but not the server runtime) (`scripts/postinstall.cjs:12`): Spawning a shell/process is command-execution capability; with unsanitized tool input it is command injection / RCE. This is read from the code itself — not from the tool description — so a poisoned server cannot hide it behind honest-looking metadata.

Evidence: { execSync } = require("child_process"); const fs = require("fs"); const path = require("path"); const platform = proce

Fix: Review this call path: confirm it never receives unsanitized tool input, constrain it, or remove it. Treat a server whose code reaches these sinks as high-capability regardless of what its tools claim.

Location: server scripts/postinstall.cjs

"screenhand" executes postinstall script(s) at install time. An install hook runs at install time; most are routine build/setup, but review what it does before trusting it.

Evidence: node scripts/postinstall.cjs

Fix: Review the scripts; install with --ignore-scripts where possible and vet what they do.

Location: package screenhand