CVE-2026-109983

Description

The YMC Filter plugin for WordPress is vulnerable to Stored DOM-Based Cross-Site Scripting via the 'post_title' parameter in all versions up to, and including, 3.12.19 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with author-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The autocomplete REST endpoint is registered with a permission callback that unconditionally returns true, meaning any site visitor — including unauthenticated users — can trigger the payload simply by typing in the YMC filter search box, while only Author-level access is required to store it.

References

• https://plugins.trac.wordpress.org/browser/ymc-smart-filter/tags/3.12.19/ymc2/assets/js/frontend/ymc-public.min.js#L10
• https://plugins.trac.wordpress.org/browser/ymc-smart-filter/tags/3.12.19/ymc2/src/api/abstracts/FG_REST_Abstract_Controller.php#L66
• https://plugins.trac.wordpress.org/browser/ymc-smart-filter/tags/3.12.19/ymc2/src/api/controllers/frontend/FG_REST_Frontend_Search_Controller.php#L135
• https://plugins.trac.wordpress.org/browser/ymc-smart-filter/tags/3.12.19/ymc2/src/api/controllers/frontend/FG_REST_Frontend_Search_Controller.php#L148
• https://plugins.trac.wordpress.org/browser/ymc-smart-filter/tags/3.12.20/ymc2/src/api/controllers/frontend/FG_REST_Frontend_Search_Controller.php