Detections
Analytics
CVE-2026-4121
medium
Description
The Kcaptcha plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to and including 1.0.1. This is due to missing nonce validation in the plugin's settings page handler (admin/setting.php). The settings form does not include a wp_nonce_field() and the form processing code does not call wp_verify_nonce() or check_admin_referer() before saving settings to the database via $wpdb->update(). This makes it possible for unauthenticated attackers to modify the plugin's CAPTCHA settings (enabling or disabling CAPTCHA on login, registration, lost password, and comment forms) via a forged request, granted they can trick a site administrator into performing an action such as clicking a link.
References
https://plugins.trac.wordpress.org/browser/kcaptcha/trunk/admin/setting.php#L47
https://plugins.trac.wordpress.org/browser/kcaptcha/trunk/admin/setting.php#L30
https://plugins.trac.wordpress.org/browser/kcaptcha/trunk/admin/setting.php#L12
https://plugins.trac.wordpress.org/browser/kcaptcha/tags/1.0.1/admin/setting.php#L47
https://plugins.trac.wordpress.org/browser/kcaptcha/tags/1.0.1/admin/setting.php#L30
https://plugins.trac.wordpress.org/browser/kcaptcha/tags/1.0.1/admin/setting.php#L12