3X-UI is a web control panel for managing Xray-core servers. Prior to 3.3.1, an authenticated administrator can abuse the database import functionality to achieve arbitrary file write on the host by modifying Xray configuration values stored in the database. This can be leveraged to obtain code execution and persistent access as the user running Xray (including root when Xray is running as root). This vulnerability is fixed in 3.3.1.