An unrestricted file upload issue in HorizontCMS 1.0.0-beta allows an authenticated remote attacker to upload PHP code through a zip file by uploading a theme, and executing the PHP file via an HTTP GET request to /themes/<php_file_name>
https://github.com/ttimot24/HorizontCMS/issues/21
https://github.com/jkana/HorizontCMS-1.0.0-beta-shell-upload