GutenKit <= 2.4.12 - Missing Authorization to Unauthenticated Sensitive Information Exposure via Mailchimp REST Endpoints

Summary

The GutenKit Blocks plugin for WordPress is vulnerable to unauthorized access of data due to a missing capability check on the /wp-json/gutenkit/v1/mailchimp/get/lists and /wp-json/gutenkit/v1/mailchimp/get/interests REST API endpoints in versions up to, and including, 2.4.12. Both endpoints are registered with permission_callback => '__return_true', and their callbacks read the site's stored Mailchimp API key from the gutenkit_settings_list option and proxy Mailchimp audience/list, merge-field, interest-category, interest-name, and subscriber-count metadata back to the caller with no login, nonce, or capability check. This makes it possible for unauthenticated attackers to retrieve private Mailchimp audience configuration information from any site that has configured the GutenKit Mailchimp integration.

Timeline

1. Jul 23, 2026, 8:34 AM UTCCVE published
2. Jul 23, 2026, 1:52 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: yes · Technical impact: partial

3. Jul 23, 2026, 1:53 PM UTCRecord last updated

Affected versions

• ataurr GutenKit – Page Builder Blocks, Patterns, and Templates for Gutenberg Block Editor

  through 2.4.12

References 10