ZimaOS is a fork of CasaOS, an operating system for Zima devices and x86-64 systems with UEFI. In version 1.2.4 and all prior versions, the ZimaOS API endpoint `http://<Zima_Server_IP:PORT>/v3/file?token=<token>&files=<file_path>` is vulnerable to arbitrary file reading due to improper input validation. By manipulating the `files` parameter, authenticated users can read sensitive system files, including `/etc/shadow`, which contains password hashes for all users. This vulnerability exposes critical system data and poses a high risk for privilege escalation or system compromise. The vulnerability occurs because the API endpoint does not validate or restrict file paths provided via the `files` parameter. An attacker can exploit this by manipulating the file path to access sensitive files outside the intended directory. As of time of publication, no known patched versions are available.