CVE-2026-94267: Advanced Custom Fields: Extended < 0.9.2.8 - Unauthenticated RCE via Front-End Post Update Action
The Advanced Custom Fields: Extended WordPress plugin before 0.9.2.8, Advanced Custom Fields: Extended PRO WordPress plugin before 0.9.2.8 does not perform any capability check when updating a post through one of its front-end form actions, allowing unauthenticated visitors to overwrite arbitrary posts, including the ones in which the site stores its own field definitions, which in turn leads to arbitrary code execution on the server. Exploitation requires the site to publish a form whose post-update action maps both its target and its content to visitor-submitted values.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Advanced Custom Fields: Extended WordPress pluginto a version that resolves this vulnerability.Fixed in 0.9.2.8 - Upgrade
Upgrade
Advanced Custom Fields: Extended PRO WordPress pluginto a version that resolves this vulnerability.Fixed in 0.9.2.8
Event History
Frequently Asked Questions
Which sites are exposed to unauthenticated exploitation?
A site is exposed if it uses an affected version of Advanced Custom Fields: Extended or Advanced Custom Fields: Extended PRO and publishes a front-end form with a post-update action whose target and content are both mapped to values submitted by visitors.
Does an attacker need an account or existing privileges?
No. The affected post-update action lacks a capability check, so an unauthenticated visitor can exploit it when the required published form configuration is present.
What can an attacker modify through the vulnerable action?
An attacker can overwrite arbitrary posts, including posts used by the site to store field definitions. Overwriting those field definitions can result in arbitrary code execution on the server.
What version should be deployed to address the issue?
Update both affected plugin editions to version 0.9.2.8 or later. Versions before 0.9.2.8 are affected.
What can be done if the plugin cannot be updated immediately?
Remove or disable published front-end forms that use a post-update action where both the target and content are derived from visitor-submitted values. Review existing forms for that configuration before re-enabling them.