CVE-2026-4121: CWE-352 Cross-Site Request Forgery (CSRF) in ksolves Kcaptcha
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.
AI Analysis
Technical Summary
CVE-2026-4121 is a CSRF vulnerability in the ksolves Kcaptcha WordPress plugin affecting all versions up to 1.0.1. The plugin's settings page handler (admin/setting.php) does not implement nonce protection mechanisms (wp_nonce_field() and wp_verify_nonce()), allowing unauthenticated attackers to modify plugin settings by tricking an administrator into submitting a crafted request. This can alter CAPTCHA enforcement on various forms, potentially weakening site defenses against automated abuse. The vulnerability has a CVSS 3.1 base score of 4.3 (medium severity), reflecting low complexity and no required privileges but limited impact to integrity only. No patch or official remediation is currently documented.
Potential Impact
An attacker can cause an authenticated site administrator to unknowingly change CAPTCHA settings via a forged request, potentially disabling CAPTCHA protections on login, registration, lost password, and comment forms. This could reduce the effectiveness of CAPTCHA defenses, increasing the risk of automated abuse or spam. The vulnerability does not allow direct compromise of confidentiality or availability, only limited integrity impact on plugin configuration.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, administrators should exercise caution when clicking links or submitting forms while logged into WordPress admin areas. Monitoring for plugin updates from ksolves is recommended to apply any official fixes once released.
CVE-2026-4121: CWE-352 Cross-Site Request Forgery (CSRF) in ksolves Kcaptcha
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.
CVSS v3.1
Score 4.3medium
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-4121 is a CSRF vulnerability in the ksolves Kcaptcha WordPress plugin affecting all versions up to 1.0.1. The plugin's settings page handler (admin/setting.php) does not implement nonce protection mechanisms (wp_nonce_field() and wp_verify_nonce()), allowing unauthenticated attackers to modify plugin settings by tricking an administrator into submitting a crafted request. This can alter CAPTCHA enforcement on various forms, potentially weakening site defenses against automated abuse. The vulnerability has a CVSS 3.1 base score of 4.3 (medium severity), reflecting low complexity and no required privileges but limited impact to integrity only. No patch or official remediation is currently documented.
Potential Impact
An attacker can cause an authenticated site administrator to unknowingly change CAPTCHA settings via a forged request, potentially disabling CAPTCHA protections on login, registration, lost password, and comment forms. This could reduce the effectiveness of CAPTCHA defenses, increasing the risk of automated abuse or spam. The vulnerability does not allow direct compromise of confidentiality or availability, only limited integrity impact on plugin configuration.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, administrators should exercise caution when clicking links or submitting forms while logged into WordPress admin areas. Monitoring for plugin updates from ksolves is recommended to apply any official fixes once released.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- Wordfence
- Date Reserved
- 2026-03-13T13:31:45.845Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 69e8876e19fe3cd2cd808e46
Added to database: 4/22/2026, 8:31:42 AM
Last enriched: 4/29/2026, 11:03:43 AM
Last updated: 6/6/2026, 11:01:13 PM
Views: 47
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