Auth bypass in Gamaup Blocks For Acf Fields — Display Custom In The Block Editor

CVE-2026-12428

The Blocks for ACF Fields plugin for WordPress is vulnerable to unauthorized access of data due to a missing capability check on the get_all_values() function in the /wp-json/acf-field-blocks/v1/values REST endpoint in versions up to, and including, 1.6.2. The permission_callback only verifies the generic publish_posts capability and the handler passes a user-supplied id parameter directly to get_field_objects() without verifying that the requesting user is authorized to read the target object. This makes it possible for authenticated attackers, with Author-level access and above, to read ACF field values from arbitrary posts (including private posts, drafts, posts by other users, and other ACF-supported objects) that they should not have access to.

Vulnerability class: Broken Access Control

Published · last modified .

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.005 (39.1th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 39th percentile — 39.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-12428: held from 0.005 to 0.005.

EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-12428?
CVE-2026-12428 is a medium-severity vulnerability in Gamaup Blocks For Acf Fields — Display Custom In The Block Editor, classified under Missing Authorization. CVSS score: 6.5/10. Published 2026-07-09.
How severe is CVE-2026-12428?
Medium severity. CVSS v3 base score is 6.5 out of 10.