Smart Custom Fields <= 5.0.6 - Missing Authorization to Authenticated (Contributor+) Sensitive Information Exposure via Relational Post Search
Strategic Overview
- Status
- Patched in 5.0.7
- Affected Plugin
- Smart Custom Fields
- Affected Version
<= 5.0.6- CVSS
- 4.3Medium
- Weakness type
- CWE-862 · Missing Authorization
- CVE
CVE-2026-4066
At a glance
CVE-2026-4066 is a medium-severity Missing Authorization vulnerability in the Smart Custom Fields WordPress plugin, affecting versions <= 5.0.6. It carries a CVSS score of 4.3 (reachable over the network; low attack complexity). Exploitation requires an authenticated account at Contributor level or above. The issue is fixed in version 5.0.7; sites on affected versions should update now. Disclosed March 2026, reported by normaandersonfrank.
Vulnerability Overview
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.
Technical Analysis
The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no interaction from a victim user.
CWE-862: Missing Authorization
Smart Custom Fields <= 5.0.6 carries this weakness at relational_posts_search(), and reaching it takes an account at Contributor level or above. A missing authorization check means a function is reachable by anyone who can reach the endpoint, because the code never asks whether the caller is allowed to perform the action.
Any user who can reach the endpoint gets to run an action reserved for higher-privileged roles, from reading protected data to changing settings or content. For Smart Custom Fields the fix is 5.0.7: builds <= 5.0.6 are affected, anything from 5.0.7 onward is not.
Remediation
Update to version 5.0.7, or a newer patched version
How does WordSec protect against this?
Because it turns on account access, WordSec's login security is the relevant layer: role-based two-factor, captcha and brute-force limits raise the cost of getting the account this needs. None of that substitutes for the fix: Smart Custom Fields 5.0.7 closes this, and updating the plugin is the step that ends it.
- Login Security
- Alerts
External References
Related records
Same weakness class
Other vulnerabilities in Smart Custom Fields
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