The Optimole WordPress plugin before 4.2.13 does not escape unrecognized attributes of its video...

The Optimole WordPress plugin before 4.2.13 does not escape unrecognized attributes of its video-player block before rendering them onto the block's wrapper element, allowing users with the Author role and above to store an event-handler attribute that executes scripts in the browser of any user, such as an administrator, who views the post.