Blog2Social: Social Media Auto Post & Scheduler <= 9.1.0 - Missing Authorization to Authenticated (Contributor+) Arbitrary Modification via Multiple AJAX Handlers

The Blog2Social: Social Media Auto Post & Scheduler plugin for WordPress is vulnerable to authorization bypass in all versions up to, and including, 9.1.0. This is due to the plugin not properly verifying that a user is authorized to perform an action. This makes it possible for authenticated attackers, with contributor-level access and above, to view, modify, or delete other users' Blog2Social records, including disclosing another user's network authentication IDs and scheduled post content, overwriting Open Graph and Twitter Card post metadata on posts they do not own, rebinding another user's social-network authorization, and mass-hiding all users' scheduled posts sitewide. The plugin's b2s_security_nonce is emitted on the post-edit meta box, which Contributors can render, making the nonce available to any authenticated user at that role level or above.