Super Forms <= 6.3.316 - Unauthenticated Arbitrary Directory Deletion via 'data[...][files][][subdir]' Parameter

The Super Forms – Drag & Drop Form Builder plugin for WordPress is vulnerable to Arbitrary Directory Deletion in all versions up to, and including, 6.3.316 via the submit_form function. This is due to insufficient validation of attacker-controlled JSON field declarations against the actual form schema, combined with a non-effective ABSPATH guard that dirname() trivially bypasses by stripping the trailing slash. This makes it possible for unauthenticated attackers to recursively delete arbitrary directories on the server, including the WordPress root directory. Exploitation requires that an administrator has enabled the 'Delete files from server after form submissions' setting, though this is a documented and commonly-enabled feature.