Kcaptcha WordPress Plugin CVE-2026-4121

| EUVD-2026-24664 MEDIUM
Cross-Site Request Forgery (CSRF) (CWE-352)
2026-04-22 Wordfence GHSA-j4g7-gjv8-gvjh
4.3
CVSS 3.1
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CVSS VectorNVD

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

Lifecycle Timeline

1
Analysis Generated
Apr 22, 2026 - 10:02 vuln.today

DescriptionNVD

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.

AnalysisAI

The Kcaptcha WordPress plugin versions up to 1.0.1 fails to validate nonces on the settings page, allowing unauthenticated attackers to modify CAPTCHA configuration (enable/disable on login, registration, lost password, and comment forms) via cross-site request forgery if a site administrator can be tricked into clicking a malicious link. The vulnerability requires user interaction (administrator click) but carries a CVSS score of 4.3 with integrity impact; no public exploit code or active exploitation has been identified at the time of analysis.

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CVE-2026-4121 vulnerability details – vuln.today

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