What’s Vulnerable › Vulnerabilities

CVE-2026-15827: GutenKit <= 2.4.12 - Missing Authorization to Unauthenticated Sensitive Information Exposure via Mailchimp REST Endpoints

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-23 · updated 2026-07-23
• Weakness: CWE-862

Description

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.

Affected products

• ataurr GutenKit – Page Builder Blocks, Patterns, and Templates for Gutenberg Block Editor: through 2.4.12

References

• https://plugins.trac.wordpress.org/browser/gutenkit-blocks-addon/tags/2.4.11/includes/Routes/MailChimp.php#L141
• https://plugins.trac.wordpress.org/browser/gutenkit-blocks-addon/tags/2.4.11/includes/Routes/MailChimp.php#L17
• https://plugins.trac.wordpress.org/browser/gutenkit-blocks-addon/tags/2.4.11/includes/Routes/MailChimp.php#L43
• https://plugins.trac.wordpress.org/browser/gutenkit-blocks-addon/tags/2.4.11/includes/Routes/MailChimp.php#L62
• https://plugins.trac.wordpress.org/browser/gutenkit-blocks-addon/tags/2.4.6/includes/Routes/MailChimp.php#L141
• https://plugins.trac.wordpress.org/browser/gutenkit-blocks-addon/tags/2.4.6/includes/Routes/MailChimp.php#L17
• https://plugins.trac.wordpress.org/browser/gutenkit-blocks-addon/tags/2.4.6/includes/Routes/MailChimp.php#L43
• https://plugins.trac.wordpress.org/browser/gutenkit-blocks-addon/tags/2.4.6/includes/Routes/MailChimp.php#L62
• https://plugins.trac.wordpress.org/changeset?reponame=&old=3618270%40gutenkit-blocks-addon&new=3618270%40gutenkit-blocks-addon
• https://www.wordfence.com/threat-intel/vulnerabilities/id/7430594c-3a71-4b24-875b-014e03be868f?source=cve

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