FileRun before 2026.3.0 contains an OS command injection vulnerability caused by a no-op redefinition of escapeshellcmd() in CLI.php that strips shell-metacharacter escaping, allowing attacker-controlled input to reach an exec() sink unsanitized. Attackers can exploit this through an interactive path via image_preview.php with a crafted args parameter requiring superuser authentication, or through a persistent path by storing malicious payloads in thumbnails_ffmpeg_args or thumbnails_ffmpeg_ss that execute when any user triggers video thumbnail generation.