Mobile Next is an MCP server for mobile development and automation. Prior to version 0.0.49, the `@mobilenext/mobile-mcp` server contains a Path Traversal vulnerability in the `mobile_save_screenshot` and `mobile_start_screen_recording` tools. The `saveTo` and `output` parameters were passed directly to filesystem operations without validation, allowing an attacker to write files outside the intended workspace. Version 0.0.49 fixes the issue.

Affected: npm: @mobilenext/mobile-mcp

### Summary The `@mobilenext/mobile-mcp` server contains a Path Traversal vulnerability in the `mobile_save_screenshot` and `mobile_start_screen_recording` tools. The `saveTo` and `output` parameters were passed directly to filesystem operations without validation, allowing an attacker to write files outside the intended workspace.

### Details **File:** `src/server.ts` (lines 584-592)

```typescript tool( "mobile_save_screenshot", "Save Screenshot", "Save a screenshot of the mobile device to a file", { device: z.string().describe("The device identifier..."), saveTo: z.string().describe("The path to save the screenshot to"), }, { destructiveHint: true }, async ({ device, saveTo }) => { const robot = getRobotFromDevice(device); const screenshot = await robot.getScreenshot(); fs.writeFileSync(saveTo, screenshot); // ← VULNERABLE: No path validation return `Screenshot saved to: ${saveTo}`; }, ); ```

### Root Cause

The `saveTo` parameter is passed directly to `fs.writeFileSync()` without any validation. The codebase has validation functions for other parameters (`validatePackageName`, `validateLocale` in `src/utils.ts`) but **no path validation function exists**.

### Additional Affected Tool

**File:** `src/server.ts` (lines 597-620)

The `mobile_start_screen_recording` tool has the same vulnerability in its `output` parameter.

### PoC ```py #!/usr/bin/env python3

import json import os import su…