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 Kcaptcha WordPress plugin (up to version 1.0.1) caused by the absence of nonce validation in the settings page handler (admin/setting.php). The plugin's settings form lacks a wp_nonce_field(), and the processing code does not verify nonces via wp_verify_nonce() or check_admin_referer() before updating the database. This flaw enables unauthenticated attackers to modify CAPTCHA-related settings by tricking an administrator into performing a crafted request.
Potential Impact
An attacker can cause unauthorized changes to the plugin's CAPTCHA settings, potentially weakening the CAPTCHA protections on login, registration, lost password, and comment forms. This could increase the risk of automated abuse or spam but does not directly compromise data confidentiality or system availability.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, administrators should avoid clicking untrusted links while logged into WordPress admin or consider disabling the plugin temporarily. 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.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-4121 is a CSRF vulnerability in the Kcaptcha WordPress plugin (up to version 1.0.1) caused by the absence of nonce validation in the settings page handler (admin/setting.php). The plugin's settings form lacks a wp_nonce_field(), and the processing code does not verify nonces via wp_verify_nonce() or check_admin_referer() before updating the database. This flaw enables unauthenticated attackers to modify CAPTCHA-related settings by tricking an administrator into performing a crafted request.
Potential Impact
An attacker can cause unauthorized changes to the plugin's CAPTCHA settings, potentially weakening the CAPTCHA protections on login, registration, lost password, and comment forms. This could increase the risk of automated abuse or spam but does not directly compromise data confidentiality or system availability.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, administrators should avoid clicking untrusted links while logged into WordPress admin or consider disabling the plugin temporarily. 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: 4/22/2026, 8:48:50 AM
Last updated: 4/23/2026, 12:48:55 AM
Views: 5
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