# Advanced Custom Fields (ACF®) <= 6.8.10 - Authenticated (Contributor+) Missing Authorization to Bidirectional Relationship Modification

- **ID:** WPSEC-2026-2419
- **Plugin:** Advanced Custom Fields (ACF®) (`advanced-custom-fields`), https://wordpress.org/plugins/advanced-custom-fields/
- **Affected versions:** from 6.2.0 before 6.8.11
- **Fixed in:** 6.8.11 (Update to 6.8.11 or later.)
- **Severity:** Medium 4.3 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N)
- **Weakness:** CWE-862
- **Usage among sites WPSec scans:** plugin Medium, affected versions Medium (as of 2026-11-03)
- **Attack surface analysis:** https://attacksurface.wpsec.com/plugin/advanced-custom-fields
- **Fix released:** 2026-11-02
- **Published:** 2026-11-03
- **URL:** https://wpsec.com/vuln/WPSEC-2026-2419/

## Description

The Advanced Custom Fields (ACF®) plugin for WordPress is vulnerable to unauthorized modification of data in all versions up to, and including, 6.8.10 due to a missing capability check when bidirectional relationship fields sync references. The plugin wrote back-references onto target posts, users and terms without checking whether the current user could edit or assign them. This makes it possible for authenticated attackers with contributor-level access and above to modify relational field values stored on posts, terms and users they are not allowed to edit.

## References

- https://wpsec.com/vuln/WPSEC-2026-2419/
- https://plugins.svn.wordpress.org/advanced-custom-fields/tags/6.8.11/
- https://wordpress.org/plugins/advanced-custom-fields/

Source: WPSec, https://wpsec.com/vuln/WPSEC-2026-2419/

License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Free to use, share and adapt, also commercially, if you credit WPSec and link to this advisory.