FreePBX Endpoint Manager is a module for managing telephony endpoints in FreePBX systems. In versions prior to 16.0.92 for FreePBX 16 and versions prior to 17.0.6 for FreePBX 17, the Endpoint Manager module contains an authenticated arbitrary file upload vulnerability affecting the fwbrand parameter. The fwbrand parameter allows an attacker to change the file path. Combined, these issues can result in a webshell being uploaded. Authentication with a known username is required to exploit this vulnerability. Successful exploitation allows authenticated users to upload arbitrary files to attacker-controlled paths on the server, potentially leading to remote code execution. This issue has been patched in version 16.0.92 for FreePBX 16 and version 17.0.6 for FreePBX 17.