CVE-2026-4139: Chsxf Mcatfilter

Medium severity, CVSS 4.3. EPSS: 0.2% chance of exploitation in the next 30 days.

The mCatFilter plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to and including 0.5.2. This is due to the complete absence of nonce verification and capability checks in the compute_post() function, which processes settings updates. The compute_post() function is called in the plugin constructor on every page load via the plugins_loaded hook, and it directly processes $_POST data to modify plugin settings via update_option() without any CSRF token validation. This makes it possible for unauthenticated attackers to modify all plugin settings, including category exclusion rules, feed exclusion flags, and tag page exclusion flags, via a forged POST request, granted they can trick a site administrator into performing an action such as clicking a link.

Affected products

• Chsxf Mcatfilter: up to and including 0.5.2

Published 2026-04-22. Last modified 2026-06-17.