The Meta Box AIO plugin for WordPress is vulnerable to Privilege Escalation to Administrator in versions up to, and including, 3.11.0. This is due to a chained flaw: the populateviaquerystring() function in the mb-frontend-submission component unconditionally overrides the form's target objectid from the GET parameter 'rwmbfrontendfieldobjectid' without any authorization check, and Form::process() lacks the usercanedit() check present in render(), allowing unauthenticated attackers to overwrite the postcontent of any page with an arbitrary shortcode via wpupdatepost(); the mb-user-profile component then directly trusts the 'role' and 'autologin' shortcode attributes in the injected [mbuserprofileregister] shortcode with no role validation. This makes it possible for unauthenticated attackers to elevate their privileges to Administrator. The standalone plugins Meta Box Frontend Submission (in versions up to 4.5.6) and Meta Box User Profile (versions up to 3.11.0) are also affected.

Contributor Arbitrary File Deletion in Meta Box – WordPress Custom Fields Framework <= 5.11.1 versions.

The Meta Box WordPress plugin before 5.13.1 does not verify that a user is authorized to delete the supplied attachment before deleting it, allowing users with a low-privilege role such as Contributor to permanently delete arbitrary media attachments belonging to other users.

The Meta Box WordPress plugin before 5.9.4 does not prevent users with at least the contributor role from access arbitrary custom fields assigned to other user's posts.