motionEye vulnerable to RCE via unsanitized motion config parameter

Summary

A command injection vulnerability in MotionEye allows attackers to achieve Remote Code Execution (RCE) by supplying malicious values in configuration fields exposed via the Web UI. Because MotionEye writes user-supplied values directly into Motion configuration files without sanitization, attackers can inject shell syntax that is executed when the Motion process restarts. This issue enables full takeover of the MotionEye container and potentially the host environment (depending on container privileges).

Details

Root Cause:

MotionEye accepts arbitrary strings from fields such as image_file_name and movie_filename in the Web UI. These are written directly into /etc/motioneye/camera-*.conf. When MotionEye restarts the Motion service (motionctl.start), the Motion binary reads this configuration. Because Motion treats these fields as shell-expandable, injected characters (e.g. $(), backticks) are interpreted as shell commands.

Vulnerability flow:

Dashboard (Web UI) ↓ ConfigHandler.set_config() ↓ camera-*.conf written ↓ motionctl.restart() ↓ Motion parses config → executes payload

Affected code:

The issue arises in how config.py handles user input before writing to config files. No sanitization or allowlisting is applied to filename fields.

Proof of Concept (PoC)

The following steps reproduce the Remote Code Execution (RCE) vulnerability in MotionEye.
Tested using the official Docker image.

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Environment Setup

1. Start MotionEye container
   Launch the vulnerable container:

   docker run -d --name motioneye -p 9999:8765 ghcr.io/motioneye-project/motioneye:edge
   

2. Verify version
   Confirm the running version inside logs:

   docker logs motioneye | grep "motionEye server"
   

   Result:

   motionEye server 0.43.1b4
   

   <img width="741" height="168" alt="version_ver" src="https://github.com/user-attachments/assets/ac85d238-da7f-4274-9381-0119c01a1320" />

3. Container shell access (for verification later)
   Keep a shell handy to verify results:

   docker exec -it motioneye /bin/bash
   ls -la /tmp
   

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Exploitation Steps

4. Access Web Interface

   <img width="1623" height="869" alt="add_camera" src="https://github.com/user-attachments/assets/d506a891-8b80-4b69-84f2-b195fcaca0cc" />