CVE-2026-4121 Kcaptcha <= 1.0.1 - Cross-Site Request Forgery to Settings Update
Attackers can trick administrators into modifying CAPTCHA settings via CSRF, potentially disabling security features on key forms.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-4121?
CVE-2026-4121 is a medium-severity vulnerability in ksolves Kcaptcha, published on 22 Apr 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official 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.
Weakness: CWE-352
Which versions are affected by CVE-2026-4121?
How do I fix CVE-2026-4121?
No fix has been published for CVE-2026-4121 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-4121 being exploited?
There is no known exploitation of CVE-2026-4121 in the wild and no public exploit code.
Sources
Also known as GHSA-j4g7-gjv8-gvjh.