CVE-2026-13355
CRITICALCVE-2026-13355 is a critical-severity (CVSS 9.8) Improper Privilege Management vulnerability. No vendor fix is recorded yet; mitigation options are listed below.
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()…
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.
Detection & mitigation playbook
VulnerabilityDetect
Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`). Because exploitation targets the running service rather than your application code, O3 also flags the exploit behaviour from runtime telemetry and egress traffic.
Remediation status
No fixed release is recorded for CVE-2026-13355 yet. Track the upstream advisory, and apply the exposure-reduction steps below in the meantime.
Mitigate without a patch
Reduce reachability while you patch: restrict network access to the service to trusted sources, disable or gate the affected component where your deployment allows it, and add a WAF/IPS signature if one exists for CVE-2026-13355. O3's runtime protection blocks the improper privilege management flaw at execution, which holds the line on hosts you cannot patch immediately.
How O3 protects you
O3 detects and blocks CVE-2026-13355 exploitation at runtime with eBPF exploit-chain detection, plus L7 egress monitoring that catches a post-exploitation callback and cuts the attacker's outbound channel.
Tailored to CVE-2026-13355. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-13355 in your dependencies?
O3 Security finds CVE-2026-13355 across dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.