Responsive Lightbox & Gallery < 2.5.4 - Authenticated (Author+) Server-Side Request Forgery

Description

The Responsive Lightbox & Gallery plugin for WordPress is vulnerable to Server-Side Request Forgery in all versions up to, and including, 2.5.3 via the 'get_image_size_by_url' function. This is due to insufficient validation of user-supplied URLs when determining image dimensions for gallery items. This makes it possible for authenticated attackers, with Author-level access and above, to make web requests to arbitrary locations originating from the web application which can be used to query and modify information from internal services.