The Meta Box AIO plugin for WordPress is vulnerable to Missing Authorization via the template_redirect dispatcher in the MB Frontend Submission extension in versions up to, and including, 3.8.0. This is due to the handle_request() function routing the mbfs_delete action without any capability or ownership check, and the nonce verification in check_ajax() being gated behind is_ajax() which is false for template_redirect requests, making it bypassable. This makes it possible for unauthenticated attackers to delete arbitrary posts and pages by supplying an attacker-controlled post ID via the rwmb_frontend_field_object_id GET parameter on any page that hosts a frontend submission form regardless of whether allow_delete is enabled.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
None
No data leak
Integrity
High
Complete data modification
Availability
High
Complete denial of service
CVSS Vector v3.1