Description
The Echo Knowledge Base – Documentation, FAQs, Chat & Smart Search plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the 'new_kb_config' parameter (specifically the article-mobile-break-point-v2 key, among other config keys interpolated into the <style> element) in versions up to, and including, 17.214.0 This is due to insufficient input sanitization and output escaping in EPKB_Frontend_Editor::fe_preview_config() and EPKB_Articles_Setup: on every knowledge base article page view, when the request supplies epkb_fe_reload_mode=on, an attacker-controlled JSON blob is merged over the stored KB configuration and several values are concatenated directly into a stylesheet emitted inside a literal <style> element without escaping (minify_css() does not strip <, > or /). This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user (with Editor-level access or above, holding the manage_categories capability, or an Administrator) into performing an action such as clicking on a specially crafted link.
References
https://www.wordfence.com/threat-intel/vulnerabilities/id/3bfab9cf-4ccb-45fc-83ce-b5250f0f6482?source=cve
https://plugins.trac.wordpress.org/changeset?reponame=&new=3727647%40echo-knowledge-base%2Ftags%2F17.311.0&old=3672811%40echo-knowledge-base%2Ftags%2F17.214.0
https://plugins.trac.wordpress.org/changeset/3727663/echo-knowledge-base/trunk/includes/admin/editor/class-epkb-frontend-editor.php
https://plugins.trac.wordpress.org/browser/echo-knowledge-base/tags/17.214.0/includes/features/layouts/class-epkb-layouts-setup.php#L45
https://plugins.trac.wordpress.org/browser/echo-knowledge-base/tags/17.214.0/includes/features/articles/class-epkb-articles-setup.php#L319
https://plugins.trac.wordpress.org/browser/echo-knowledge-base/tags/17.214.0/includes/features/articles/class-epkb-articles-setup.php#L131
https://plugins.trac.wordpress.org/browser/echo-knowledge-base/tags/17.214.0/includes/class-epkb-utilities.php#L836
https://plugins.trac.wordpress.org/browser/echo-knowledge-base/tags/17.214.0/includes/admin/editor/class-epkb-frontend-editor.php#L848
https://plugins.trac.wordpress.org/browser/echo-knowledge-base/tags/17.214.0/includes/admin/editor/class-epkb-frontend-editor.php#L1072
https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-111818
