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Vulnerabilities

Vulnerability · CVE-2026-8809

acfextended advanced_custom_fields_extended Improper Privilege Management

Published May 28, 2026 · catalog updated Oct 13, 2026 · acfextended advanced_custom_fields_extended Improper Privilege

Patch now

CVE-2026-8809 is in the CISA known-exploited catalog. Confirm acfextended advanced_custom_fields_extended Improper Privilege against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (acfextended advanced_custom_fields_extended Improper Privilege).
Severity
Critical9.8
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
0.87%
Remediation
Remediation guidance
Affected products
stated advanced_custom_fields_extended · vendor acfextended advanced_custom_fields_extended

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • stated advanced_custom_fields_extended<= 0.9.2
  • vendor acfextended advanced_custom_fields_extendedversion unspecified

How to fix CVE-2026-8809

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2026-8809 is in the CISA known-exploited catalog. Confirm acfextended advanced_custom_fields_extended Improper Privilege against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Compare what you have installed with <= 0.9.2. Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

What should an analyst verify?

CWE-269: Improper Privilege Management. EPSS 0.87%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

WordPress security

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 13, 2026 · VulnCheck KEV

    Detected

    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 sil

  2. Oct 13, 2026 · CISA KEV

    Known exploited

    Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

Sources

  • CVE.orgVulnerability recordCVE-2026-8809

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-8809

    30-day exploitation probability 0.9%

    first.org
  • NIST NVDVulnerability recordCVE-2026-8809

    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-control

    nvd.nist.gov
  • VulnCheck KEVConfirmed exploitationCVE-2026-8809

    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-control

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.