CVE-2026-8809: Advanced Custom Fields: Extended (WordPress plugin) · Improper Privilege Management
Affects Advanced Custom Fields: Extended (WordPress plugin)Source CVE Database V5
Not known to be exploited · CVSS 9.8 Critical.
Data as of 29 Oct 2026, 19:04 UTC
- EPSS
- 0.8% chance of exploitation in 30 days – higher than 56% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 28 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: evidence found.
Public exploit code: GitHub proofs of concept
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), GitHub proofs of concept, the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| hwk-frAdvanced Custom Fields: Extended | Affected
| Fixed in– |
AI-suggested
Until an official fix is available, restrict or disable public ACFE frontend forms configured with Create User actions that map role fields to prevent exploitation. Monitor vendor channels for updates and apply patches promptly once released.
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.
References
- wordfence.com/threat-intel/vulnerabilities/id/bd332f49-5aa9-4207-89db-84692a6430e0?source=cve (opens in a new tab)
- plugins.trac.wordpress.org/browser/acf-extended/tags/0.9.2.4/includes/module-acf.php (opens in a new tab)
- plugins.trac.wordpress.org/browser/acf-extended/tags/0.9.2.4/includes/hooks.php (opens in a new tab)
- plugins.trac.wordpress.org/browser/acf-extended/tags/0.9.2.4/includes/modules/form/module-form-action-user.php (opens in a new tab)
- plugins.trac.wordpress.org/browser/acf-extended/tags/0.9.2.4/includes/modules/form/module-form-front.php (opens in a new tab)
- plugins.trac.wordpress.org/changeset/3551665/acf-extended (opens in a new tab)