cve-2026-8809

HIGH vulncheck_kev
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.

Timeline
Published
2026-10-13 00:00 UTC
Last Modified
2026-10-13
CVSS Details

CVSS details not available.

Affected Products

No product information available.

References

No references available.

Linked Vulnerabilities

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"
}
Enrichment data
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