CVE-2026-8809 PUBLISHED

Advanced Custom Fields: Extended <= 0.9.2.5 - Unauthenticated Privilege Escalation via Validation Bypass to '_acf_post_id' Parameter

Assigner: Wordfence
Reserved: 18.05.2026 Published: 28.05.2026 Updated: 28.05.2026

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.

Metrics

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

Product Status

Vendor hwk-fr
Product Advanced Custom Fields: Extended
Versions Default: unaffected
  • affected from 0 to 0.9.2.5 (incl.)

Credits

  • daroo finder

References

Problem Types

  • CWE-269 Improper Privilege Management CWE