Vulnerability · Published Apr 22, 2026 · Assigned by Wordfence
CVE-2026-4121Kcaptcha <= 1.0.1 - Cross-Site Request Forgery to Settings Update
Medium 4.3
In plain English
A medium-severity cross-site request forgery in Kcaptcha from ksolves. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 7% of all known vulnerabilities).
Official 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.
Affected products (as reported)
Weakness: CWE-352 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
References
- https://www.wordfence.com/threat-intel/vulnerabilities/id/a6c1c73b-76e3-4cb9-ad53-9d5d4e7519c9?source=cve
- 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#L12
- https://plugins.trac.wordpress.org/browser/kcaptcha/trunk/admin/setting.php#L30
- https://plugins.trac.wordpress.org/browser/kcaptcha/tags/1.0.1/admin/setting.php#L30
- https://plugins.trac.wordpress.org/browser/kcaptcha/trunk/admin/setting.php#L47
- https://plugins.trac.wordpress.org/browser/kcaptcha/tags/1.0.1/admin/setting.php#L47