hwk-fr Advanced Custom Fields Plugin up to 0.9.2.5 on WordPress POST Parameter validate_front_value privileges management

Summaryinfo

A vulnerability classified as critical was found in hwk-fr Advanced Custom Fields Plugin up to 0.9.2.5 on WordPress. Impacted is the function acfe_field_user_roles::validate_front_value of the component POST Parameter Handler. Executing a manipulation can lead to privileges management. This vulnerability appears as CVE-2026-8809. The attack may be performed from remote. There is no available exploit. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in hwk-fr Advanced Custom Fields Plugin up to 0.9.2.5 on WordPress. It has been declared as critical. This vulnerability affects the function acfe_field_user_roles::validate_front_value of the component POST Parameter Handler. The manipulation with an unknown input leads to a privileges management vulnerability. The CWE definition for the vulnerability is CWE-269. The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

The Advanced Custom Fields: Extended plugin for WordPress is vulnerable to Privilege Escalation via Validation Bypass in all versions up to and including 0.9.2.5. The vulnerability exists due to the after_validate_save_post() function unconditionally trusting the attacker-controlled _acf_post_id POST parameter — with no authentication or integrity verification — to select a cleanup branch that silently discards all validation errors not prefixed with acfe:. This makes it possible for unauthenticated attackers to suppress both the role allow-list validation error added by acfe_field_user_roles::validate_front_value() and the administrator-role capability guard error added by acfe_module_form_action_user::validate_action(), causing wp_insert_user() to execute with an attacker-supplied administrator role argument and resulting in the creation of a new administrator-level user account. Exploitation requires the target site to expose a public ACFE frontend form configured with a Create User action that maps a role field.

The weakness was presented by daroo. The advisory is shared for download at wordfence.com. This vulnerability was named CVE-2026-8809 since 05/18/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1068.

Upgrading to version 0.9.2.4 eliminates this vulnerability.

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Productinfo

Type

• WordPress Plugin

Vendor

• hwk-fr

Name

• Advanced Custom Fields Plugin

Version

• 0.9.2.0
• 0.9.2.1
• 0.9.2.2
• 0.9.2.3
• 0.9.2.4
• 0.9.2.5

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CPE 2.2info

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