The SlideshowPluginSlideshowStylesheet::loadStylesheetByAJAX function in the Slideshow plugin 2.2.8 through 2.2.21 for Wordpress allows remote attackers to read arbitrary Wordpress option values.
https://wordpress.org/plugins/slideshow-jquery-image-gallery/#developers
https://github.com/Boonstra/Slideshow/commit/cac505e593cbe70a4d8af5b639f5385d4cc7aa04