CVE-2026-4561: Dvankooten MC4WP: Mailchimp For WordPress

Medium severity, CVSS 6.4. EPSS: 0.3% chance of exploitation in the next 30 days.

The MC4WP: Mailchimp for WordPress plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the form response message post meta fields (e.g., 'text_subscribed', 'text_error') in all versions up to, and including, 4.12.0 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with Author-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

Affected products

• Dvankooten MC4WP: Mailchimp For WordPress: up to and including 4.12.0

Published 2026-08-22. Last modified 2026-08-24.