The Yoast Duplicate Post plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the clone_bulk_action_handler() and republish_request() functions in all versions up to, and including, 4.5. This makes it possible for authenticated attackers, with Contributor-level access and above, to duplicate any post on the site including private, draft, and trashed posts they shouldn't have access to. Additionally, attackers with Author-level access and above can use the Rewrite & Republish feature to overwrite any published post with their own content.