CVE-2026-13355

CRITICAL
Published Sep 22, 2026 Modified Sep 22, 2026 CWE-269

Description

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 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 3.11.0) are also affected.

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CVSS v3.1 Score

9.8
CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0044
Probability of exploitation
0.37%
Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-269 CWE-269

References

Frequently Asked Questions

What is CVE-2026-13355? +
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 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 3.11.0) are also affected. It has a CVSS v3.1 base score of 9.8 (CRITICAL).
How severe is CVE-2026-13355? +
CVE-2026-13355 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0044, placing it in the 0th percentile for exploitation probability.
How do I check if I'm vulnerable to CVE-2026-13355? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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