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CVE-2026-4121

4.3 · MEDIUM

The Kcaptcha plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to and including 1.0.1.

Published Apr 22, 2026CWE-352EPSS 0.20%

Overview

CVE-2026-4121 is a medium-severity vulnerability. It was published on April 22, 2026 and has a CVSS 3.1 base score of 4.3 (MEDIUM).

This vulnerability has a CVSS 3.1 base score of 4.3, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

Technical 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.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

Refplugins.trac.wordpress.org/browser/kcaptcha/tags/1.0.1/admin/setting.php#L12Refplugins.trac.wordpress.org/browser/kcaptcha/tags/1.0.1/admin/setting.php#L30Refplugins.trac.wordpress.org/browser/kcaptcha/tags/1.0.1/admin/setting.php#L47Refplugins.trac.wordpress.org/browser/kcaptcha/trunk/admin/setting.php#L12Refplugins.trac.wordpress.org/browser/kcaptcha/trunk/admin/setting.php#L30Refplugins.trac.wordpress.org/browser/kcaptcha/trunk/admin/setting.php#L47Refwww.wordfence.com/threat-intel/vulnerabilities/id/a6c1c73b-76e3-4cb9-ad53-9d5d4e7519c9?source=cve

How CyberStrike helps

Frequently asked questions

What is CVE-2026-4121?

CVE-2026-4121 is a medium-severity vulnerability. It was published on April 22, 2026 and has a CVSS 3.1 base score of 4.3 (MEDIUM).

How severe is CVE-2026-4121?

This vulnerability has a CVSS 3.1 base score of 4.3, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2026-4121?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2026-4121?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-4121 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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