PT-2026-34288 · WordPress · Captcha

Muhammad Afnaan · Published 2026-04-22 · Updated 2026-04-23 · CVE-2026-4121

Positive Technologies (AI Summary)

CVSS v3.1

4.3

Medium

Base vector

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

Name of the Vulnerable Software and Affected Versions Kcaptcha versions prior to 1.0.2

Description The Kcaptcha plugin for WordPress is subject to Cross-Site Request Forgery. The issue exists in the settings page handler 'admin/setting.php' because it lacks nonce validation. Specifically, the settings form does not implement a wp nonce field() and the processing code fails to utilize wp verify nonce() or check admin referer() before updating the database via $wpdb->update(). This allows unauthenticated attackers to modify CAPTCHA settings for login, registration, lost password, and comment forms by tricking a site administrator into clicking a malicious link.

Recommendations Update to a version newer than 1.0.1.

Fix

CSRF

Weakness Enumeration

CWE-352

Related Identifiers

CVE-2026-4121

Affected Products

Captcha

References · 10

• https://nvd.nist.gov/vuln/detail/CVE-2026-4121 · Security Note
• https://plugins.trac.wordpress.org/browser/kcaptcha/trunk/admin/setting.php#L30 · Note
• https://plugins.trac.wordpress.org/browser/kcaptcha/tags/1.0.1/admin/setting.php#L12 · Note
• https://plugins.trac.wordpress.org/browser/kcaptcha/trunk/admin/setting.php#L47 · Note
• https://plugins.trac.wordpress.org/browser/kcaptcha/tags/1.0.1/admin/setting.php#L47 · Note
• https://plugins.trac.wordpress.org/browser/kcaptcha/trunk/admin/setting.php#L12 · Note
• https://twitter.com/VulmonFeeds/status/2046943068629151796 · Twitter Post
• https://wordfence.com/threat-intel/vulnerabilities/id/a6c1c73b-76e3-4cb9-ad53-9d5d4e7519c9?source=cve · Note
• https://plugins.trac.wordpress.org/browser/kcaptcha/tags/1.0.1/admin/setting.php#L30 · Note
• https://twitter.com/CVEnew/status/2047428115560009789 · Twitter Post