CVE-2026-4066

The Smart Custom Fields plugin for WordPress is vulnerable to unauthorized access of data due to a missing capability check on the relational_posts_search() function in all versions up to, and including, 5.0.6. This makes it possible for authenticated attackers, with Contributor-level access and above, to read private and draft post content from other authors via the smart-cf-relational-posts-search AJAX action. The function queries posts with post_status=any and returns full WP_Post objects including post_content, but only checks the generic edit_posts capability instead of verifying whether the requesting user has permission to read each individual post.

The following products are affected by CVE-2026-4066 vulnerability.

Here, you will find a curated list of external links that provide in-depth information to CVE-2026-4066.

URL	Resource
https://plugins.trac.wordpress.org/browser/smart-custom-fields/trunk/classes/fields/class.field-related-posts.php#L101
https://plugins.trac.wordpress.org/browser/smart-custom-fields/trunk/classes/fields/class.field-related-posts.php#L143
https://plugins.trac.wordpress.org/browser/smart-custom-fields/trunk/classes/fields/class.field-related-posts.php#L78
https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&new=3485210%40smart-custom-fields%2Ftrunk&old=3416964%40smart-custom-fields%2Ftrunk&sfp_email=&sfph_mail=#file2
https://www.wordfence.com/threat-intel/vulnerabilities/id/87f52e3a-e414-4f47-b46c-e3811e76744b?source=cve