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CVE-2026-2839

Advanced Custom Fields: Extended <= 0.9.2.7 - Missing Authorization to Unauthenticated Data Exposure via Multiple AJAX Endpoints

5.3 Medium

The Advanced Custom Fields: Extended plugin for WordPress is vulnerable to unauthorized access of data and triggering of server-side actions in all versions up to, and including, 0.9.2.7. This is due to multiple AJAX handlers registered for unauthenticated users (wp_ajax_nopriv_*) that fail to implement proper current_user_can() authorization checks. While these handlers use ACF's acf_verify_ajax() function to validate cryptographic nonces, the acf_nonce values are generated for guest users and publicly exposed in the page source of any frontend page utilizing an ACF form. This makes it possible for unauthenticated attackers to extract the guest nonce and bypass WordPress visibility permissions, leading to the unauthorized disclosure of post titles and internal Flexible Content layout structures. The vulnerability was partially patched in version 0.9.2.4.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
Low
Integrity
None
Availability
None

Exploit likelihood

0.27%Unchanged since Oct 28, 2026
90%50%10%1%

What each source reports

CVE List Score used 5.3

Advanced Custom Fields: Extended <= 0.9.2.7 - Missing Authorization to Unauthenticated Data Exposure via Multiple AJAX Endpoints

The Advanced Custom Fields: Extended plugin for WordPress is vulnerable to unauthorized access of data and triggering of server-side actions in all versions up to, and including, 0.9.2.7. This is due to multiple AJAX handlers registered for unauthenticated users (wp_ajax_nopriv_*) that fail to implement proper current_user_can() authorization checks. While these handlers use ACF's acf_verify_ajax() function to validate cryptographic nonces, the acf_nonce values are generated for guest users and publicly exposed in the page source of any frontend page utilizing an ACF form. This makes it possible for unauthenticated attackers to extract the guest nonce and bypass WordPress visibility permissions, leading to the unauthorized disclosure of post titles and internal Flexible Content layout structures. The vulnerability was partially patched in version 0.9.2.4.

Record
CVE-2026-2839
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Weakness
CWE-862
Updated
2026-11-02
EUVDEUVD-2026-111603 5.3

The Advanced Custom Fields: Extended plugin for WordPress is vulnerable to unauthorized access of data and triggering of server-side actions in all versions up to, and including, 0.9.2.7. This is due to multiple AJAX handlers registered for unauthenticated users (wp_ajax_nopriv_*) that fail to implement proper current_user_can() authorization checks. While these handlers use ACF's acf_verify_ajax() function to validate cryptographic nonces, the acf_nonce values are generated for guest users and publicly exposed in the page source of any frontend page utilizing an ACF form. This makes it possible for unauthenticated attackers to extract the guest nonce and bypass WordPress visibility permissions, leading to the unauthorized disclosure of post titles and internal Flexible Content layout structures. The vulnerability was partially patched in version 0.9.2.4.

Record
EUVD-2026-111603
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Updated
2026-11-02
GitHub AdvisoriesGHSA-6687-wfp7-4mp6 5.3

The Advanced Custom Fields: Extended plugin for WordPress is vulnerable to unauthorized access of...

The Advanced Custom Fields: Extended plugin for WordPress is vulnerable to unauthorized access of data and triggering of server-side actions in all versions up to, and including, 0.9.2.7. This is due to multiple AJAX handlers registered for unauthenticated users (wp_ajax_nopriv_*) that fail to implement proper current_user_can() authorization checks. While these handlers use ACF's acf_verify_ajax() function to validate cryptographic nonces, the acf_nonce values are generated for guest users and publicly exposed in the page source of any frontend page utilizing an ACF form. This makes it possible for unauthenticated attackers to extract the guest nonce and bypass WordPress visibility permissions, leading to the unauthorized disclosure of post titles and internal Flexible Content layout structures. The vulnerability was partially patched in version 0.9.2.4.

Record
GHSA-6687-wfp7-4mp6
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Weakness
CWE-862
Updated
2026-11-02
NVD 5.3

The Advanced Custom Fields: Extended plugin for WordPress is vulnerable to unauthorized access of data and triggering of server-side actions in all versions up to, and including, 0.9.2.7. This is due to multiple AJAX handlers registered for unauthenticated users (wp_ajax_nopriv_*) that fail to implement proper current_user_can() authorization checks. While these handlers use ACF's acf_verify_ajax() function to validate cryptographic nonces, the acf_nonce values are generated for guest users and publicly exposed in the page source of any frontend page utilizing an ACF form. This makes it possible for unauthenticated attackers to extract the guest nonce and bypass WordPress visibility permissions, leading to the unauthorized disclosure of post titles and internal Flexible Content layout structures. The vulnerability was partially patched in version 0.9.2.4.

Record
CVE-2026-2839
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Weakness
CWE-862
Updated
2026-11-02

Affected products

History

History
RecordedChangedSources
first indexedCVE List, EUVD, GitHub Advisories, NVD

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-2839 is a medium vulnerability (CVSS 5.3) in Hwk-fr Advanced Custom Fields: Extended, published October 28, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.27%, the 20th percentile. No source names a fixed version.

References

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