The Gallery Plugin for WordPress WordPress plugin before 1.8.15 does not sanitise and escape some of its image settings, which could allow users with post-writing privilege such as Author to perform Cross-Site Scripting attacks.
The Gallery Plugin for WordPress – Envira Photo Gallery plugin for WordPress is vulnerable to unauthorized modification of data due to an improper capability check on the 'envira_gallery_insert_images' function in all versions up to, and including, 1.8.7.1. This makes it possible for authenticated attackers, with contributor access and above, to modify galleries on other users' posts.