CVE-2026-15827

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

2026-07-22 20:27
Viet Anh Ngo

Strategic Overview

Status
Patched in 2.4.13
Affected Plugin
GutenKit – Page Builder Blocks, Patterns, and Templates for Gutenberg Block Editor
Affected Version
<= 2.4.12
CVSS
5.3Medium
Weakness type
CWE-862 · Missing Authorization
CVE
CVE-2026-15827
View all GutenKit – Page Builder Blocks, Patterns, and Templates for Gutenberg Block Editor vulnerabilities

At a glance

CVE-2026-15827 is a medium-severity Missing Authorization vulnerability in the GutenKit WordPress plugin, affecting versions <= 2.4.12. It carries a CVSS score of 5.3 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 2.4.13; sites on affected versions should update now. Disclosed July 2026, reported by Viet Anh Ngo.

Vulnerability Overview

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.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site, and no interaction from a victim user.

CWE-862: Missing Authorization

GutenKit <= 2.4.12 carries this weakness at __return_true, and reaching it takes no account at all. A missing authorization check means a function is reachable by anyone who can reach the endpoint, because the code never asks whether the caller is allowed to perform the action.

Any user who can reach the endpoint gets to run an action reserved for higher-privileged roles, from reading protected data to changing settings or content. For GutenKit the fix is 2.4.13: builds <= 2.4.12 are affected, anything from 2.4.13 onward is not.

Remediation

Update to version 2.4.13, or a newer patched version

How does WordSec protect against this?

This one needs no account at all, which puts it outside what login hardening can reach; WordSec's login security narrows the account-level paths around it, and the firewall is what inspects the request itself. None of that substitutes for the fix: GutenKit 2.4.13 closes this, and updating the plugin is the step that ends it.

  • Login Security
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2026-15827https://www.wordfence.com/threat-intel/vulnerabilities/id/7430594c-3a71-4b24-875b-014e03be868fhttps://nvd.nist.gov/vuln/detail/CVE-2026-15827

Related records

Vulnerability data © Defiant, Inc., provided under the Wordfence Intelligence T&C