NVD / CVE Program· CNA Wordfence

CVE-2026-8809: Advanced Custom Fields: Extended <= 0.9.2.5 - Unauthenticated Privilege Escalation via Validation Bypass to '_acf_post_id' Parameter

Noroxi assessment

Priority: Monitor (action score 39/100)

Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
Probability of exploitation in the next 30 days: 0.80% (FIRST EPSS); higher than 56.5% of all records.
Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
According to CISA the attack is automatable: targets can be found by mass scanning.
No fixed version is recorded, but the references include a patch (commit or PR) link.
Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. See the fix and affected versions sections below.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

CriticalCVSS 9.8 · v3.1—Proof of concept No fix recorded

Pre-auth

Published: May 28, 2026
Updated: Jul 21, 2026
EPSS: 0.8% · 56th percentile
CWE: CWE-269

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 39 / 40 · 9.8 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.8%

CISA SSVC decision

Exploitation: none
Automatable: yes
Technical impact: total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · Wordfence: 9.8; NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Is Advanced Custom Fields: Extended on your site?

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Noroxi analysis

What does it mean in your environment?

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

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Versions reported by the vendor

Affected version ranges reported by the assigning authority (Wordfence). Independent of NVD's CPE analysis and usually ahead of it.

hwk-fr Advanced Custom Fields: Extended
- up to and including 0.9.2.5affected · semver

Same product

hwk-fr: all records

Other highest-scoring records for the same primary product.

CVE-2025-13486Advanced Custom Fields: Extended 0.9.0.5 - 0.9.1.1 - Unauthenticated Remote Code Execution in prepare_form
60This week
CVE-2025-14533Advanced Custom Fields: Extended <= 0.9.2.1 - Unauthenticated Privilege Escalation via Insert User Form Action
39Monitor
CVE-2026-110305Advanced Custom Fields: Extended <= 0.9.2.7 - Unauthenticated Sensitive Information Exposure in 'acf[<mapped_field>]' Parameter via {get_user} Template Tag Inje
30Monitor

Published before and after this one in the same product

← EarlierCVE-2025-15463May 12, 2026 · Advanced Custom Fields: Extended <= 0.9.2.3 - Unauthenticated Arbitrary Shortcode Execution
26Monitor
Later →CVE-2026-10752Oct 27, 2026 · Advanced Custom Fields: Extended <= 0.9.2.6 - Missing Authorization to Unauthenticated Arbitrary Attachment Deletion via Email Action Dynamic File Field
19Monitor
Later →CVE-2026-2839Oct 28, 2026 · Advanced Custom Fields: Extended <= 0.9.2.7 - Missing Authorization to Unauthenticated Data Exposure via Multiple AJAX Endpoints
21Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

Proof-of-concept repository on GitHub ×1

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
Source	Kind	Date
Proof-of-concept repository on GitHub	stars:0	2026-06-12

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

PublishedMay 28, 2026
First PoCJun 12, 2026+14 d
TodayNov 1, 2026+156 d

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

plugins.trac.wordpress.orgchangeset 3551665

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

darooPatchstack Bug Bounty Programfinder

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

CVE-2025-14533128 days apartAdvanced Custom Fields: Extended <= 0.9.2.1 - Unauthenticated Privilege Escalation via Insert User Form Action
39Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

TR-26-0287 · Jun 2, 2026(WordPress Eklenti Güvenlik Bildirimi)

All national notices →

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
No account or password is required.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: high · data can be read
Integrity: high · data or configuration can be modified
Availability: high · the service can be disrupted

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: Unchanged
Confidentiality impact: High
Integrity impact: High
Availability impact: High

Weakness class (CWE)

CWE-269 · Improper Privilege Management

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

nvd-secondary

Root cause

To simplify setup, a service account is granted broad, cluster-wide permissions. The principle of least privilege is skipped during installation.

The bug in code

The whole CWE-269 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

yaml

1kind: ClusterRole
2rules:
3  - apiGroups: ["*"]
4    resources: ["*"]
5    verbs: ["*"]

Fixed

yaml

1kind: Role
2metadata:
3  namespace: lodos-system
4rules:
5  - apiGroups: ["apps"]
6    resources: ["deployments"]
7    verbs: ["get", "list", "update"]

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

Abuse Elevation Control MechanismT1548

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

plugins.trac.wordpress.org/browser/acf-extended/tags/0.9.2.4/includes/hooks.php#L636

Show all references (5 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records