--- cve: "CVE-2026-8809" severity: "CRITICAL" cvss: 9.8 epss: "0.8%" vendor: "hwk-fr" kev: false exploited: false published: "2026-05-28 23:16:44" tags: [cve, security, critical] source: tsecurity.de CVE-Dossier exported: "2026-09-22T08:07:07+02:00" --- # CVE-2026-8809 > 9.8 CRITICAL ## Beschreibung 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. ## CVSS-Vektor ``` CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H ``` | Metrik | Wert | Bewertung | |---|---|---| | AV Angriffsvektor | Netzwerk | bad | | AC Komplexität | Gering | bad | | PR Privilegien | Keine | bad | | UI Interaktion | Keine | bad | | S Scope | Unverändert | good | | C Vertraulichkeit | Hoch | bad | | I Integrität | Hoch | bad | | A Verfügbarkeit | Hoch | bad | ## Referenzen - - - - - - --- _Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-8809) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_