Directory traversal vulnerability in the Slider Revolution (revslider) plugin before 4.2 for WordPress allows remote attackers to read arbitrary files via a .. (dot dot) in the img parameter in a revslider_show_image action to wp-admin/admin-ajax.php.
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.