Meta Box AIO <= 3.7.2 And Standalone Plugin Extensions - Unauthenticated Privilege Escalation to Administrator to 'rwmb_frontend_field_object_id' Parameter
Strategic Overview
- Status
- Patched in 3.12.0
- Affected Plugin
- Meta Box User Profile
- Affected Version
<= 3.11.0- CVSS
- 9.8Critical
- Weakness type
- CWE-269 · Improper Privilege Management
- CVE
CVE-2026-13355
At a glance
CVE-2026-13355 is a critical-severity Improper Privilege Management vulnerability in the Meta Box User Profile WordPress plugin, affecting versions <= 3.11.0. It carries a CVSS score of 9.8 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). Exploitation requires no authentication. The issue is fixed in version 3.12.0; sites on affected versions should update now. Disclosed September 2026, reported by h0xilo.
Vulnerability Overview
The Meta Box AIO plugin for WordPress is vulnerable to Privilege Escalation to Administrator in versions up to, and including, 3.7.2. This is due to a chained flaw: the populate_via_query_string() function in the mb-frontend-submission component unconditionally overrides the form's target object_id from the GET parameter 'rwmb_frontend_field_object_id' without any authorization check, and Form::process() lacks the user_can_edit() check present in render(), allowing unauthenticated attackers to overwrite the post_content of any page with an arbitrary shortcode via wp_update_post(); the mb-user-profile component then directly trusts the 'role' and 'auto_login' shortcode attributes in the injected [mb_user_profile_register] 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 2.5.14) are also affected.
Technical Analysis
The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site, and no interaction from a victim user. A successful exploit has high impact on confidentiality, integrity, availability — full site compromise territory.
CWE-269: Improper Privilege Management
Meta Box User Profile <= 3.11.0 carries this weakness at rwmb_frontend_field_object_id, and reaching it takes no account at all. Improper privilege management means the code lets an account end up with capabilities its role should not have.
It converts a low-privileged account into an administrative one, which makes every other restriction on the site irrelevant. For Meta Box User Profile the fix is 3.12.0: builds <= 3.11.0 are affected, anything from 3.12.0 onward is not.
Remediation
Update to version 3.12.0, or a newer patched version
How does WordSec protect against this?
This one needs no account at all, which puts it outside what login hardening can reach; WordSec's login security narrows the account-level paths around it, and the firewall is what inspects the request itself. None of that substitutes for the fix: Meta Box User Profile 3.12.0 closes this, and updating the plugin is the step that ends it.
- Login Security
- Alerts
External References
Vulnerability data © Defiant, Inc., provided under the Wordfence Intelligence T&C