WordPress · Mailchimp List Subscribe Form · CVE-2026-15052
**Name of the Vulnerable Software and Affected Versions**
MailChimp Subscribe Form, Optin Builder, PopUp Builder, Form Builder plugin for WordPress versions prior to 4.3.4
**Description**
Stored Cross-Site Scripting (XSS) occurs due to insufficient input sanitization and output escaping. This allows unauthenticated attackers to inject arbitrary web scripts into pages via form field values, which then execute when a user accesses the affected page.
**Recommendations**
Update the plugin to version 4.3.4 or later.