WordPress security changelog
MEDIUM CVE-2026-4121 Deferred

Kcaptcha: Cross-site request forgery

Kcaptcha is affected by cross-site request forgery. The vulnerable path is reachable without authentication. Exploitation relies on a signed-in privileged user submitting an attacker-controlled request. The published affected range is <= 1.0.1.

CVE / CNA score 4.3 CVSS 3.1 · security@wordfence.com
NVD score Pending NVD has not published its own CVSS assessment.
Component
Kcaptcha
Plugin slug
kcaptcha
Affected
<= 1.0.1
Safe version
> 1.0.1
Published
Apr 22, 2026
Weakness
CWE-352 — Cross-Site Request Forgery (CSRF)

This CVE was published Apr 22, 2026 and is one of 1 known issue for this plugin.

What to do

Update, patch or deactivate.

Update Kcaptcha to a release after 1.0.1, or disable and remove it until a fixed version is available.

A safe version is available, so updating to that version or later is the preferred remediation. If an immediate update is not practical, consider a targeted application patch or temporarily restricting the affected functionality.

Deactivate only when warranted by your risk profile, or when advised by your hosting provider in the limited circumstances where the vulnerability cannot otherwise be mitigated. If you’re unsure which action is appropriate, contact Fused or your hosting provider for guidance.

Source record

Technical 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.

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

References

Primary and upstream sources