cve-2026-8809
HIGH vulncheck_kevThe 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.
- Published
- 2026-10-13 00:00 UTC
- Last Modified
- 2026-10-13
CVSS details not available.
No product information available.
No references available.
No linked vulnerabilities found.
{
"cvss": 0.0,
"datePublished": "2026-10-13T00:00:00Z",
"dateUpdated": "2026-10-13T00:00:00Z",
"description": "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.",
"dueDate": "",
"id": "CVE-2026-8809",
"kev_catalogs": [
"vulncheck"
],
"knownRansomwareCampaignUse": "Unknown",
"product": "advanced_custom_fields_extended",
"requiredAction": "Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.",
"severity": "HIGH",
"source": "vulncheck_kev",
"title": "acfextended advanced_custom_fields_extended Improper Privilege Management",
"vendor": "acfextended"
}