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Vulnerabilities

Vulnerability · CVE-2026-4121

The Kcaptcha plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to and including 1.0.1.

Published Apr 22, 2026 · catalog updated Jun 17, 2026 · The Kcaptcha plugin for

Check if you run it

No confirmed exploitation is on record for CVE-2026-4121. EPSS is 0.20%. Act only if a listed version of The Kcaptcha plugin for is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (The Kcaptcha plugin for).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium4.3
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.20%
Remediation
Version ranges on file
Affected products
stated named in the record

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • stated named in the record<= 1.0.1

How to fix CVE-2026-4121

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-4121. EPSS is 0.20%. Act only if a listed version of The Kcaptcha plugin for is installed.

Which versions are affected?

Compare what you have installed with named in the record <= 1.0.1. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-352: Cross-Site Request Forgery (CSRF). EPSS 0.20%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

WordPress security

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Apr 22, 2026 · NIST NVD

    Detected

    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 v

  2. Jun 17, 2026 · NIST NVD

    Updated

    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 v

Sources

  • CVE.orgVulnerability recordCVE-2026-4121

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-4121

    30-day exploitation probability 0.2%

    first.org
  • NIST NVDVulnerability recordCVE-2026-4121

    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 th

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.