# CVE-2026-4121

> Vulnerability · severity: **MEDIUM** (CVSS 4.3).

## 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.

## Key facts

- **CVE ID:** CVE-2026-4121
- **Published:** 2026-04-22
- **CVSS severity:** MEDIUM
- **CVSS base score:** 4.3
- **CWE codes:** CWE-352

## Primary sources

- NIST NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-4121

## Citation

> AI Analytics. CVE-2026-4121. Retrieved 2026-07-10 from https://api.ai-analytics.org/cve/CVE-2026-4121. Derived from NIST NVD. Licensed CC0.

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