Easy Post Submission <= 2.3.0 - Missing Authorization

The Easy Post Submission plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the create_post() function in all versions up to, and including, 2.3.0. This is due to the rbsm_submit_post AJAX action being registered for unauthenticated users via wp_ajax_nopriv_rbsm_submit_post without any authorization checks when a postId parameter is supplied. This makes it possible for unauthenticated attackers to modify the title, content, excerpt, categories, and tags of arbitrary posts, as well as change the post status to draft (effectively unpublishing them) via the 'postId' parameter.