Vulnerability · Published Aug 22, 2026 · Assigned by Wordfence
CVE-2026-4561MC4WP: Mailchimp for WordPress <= 4.12.0 - Authenticated (Author+) Stored Cross-Site Scripting via Form Response Messages
Medium 6.4
In plain English
A medium-severity cross-site scripting in MC4WP: Mailchimp for WordPress from dvankooten. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 26% of all known vulnerabilities).
Official description
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 (as reported)
| Vendor | Product | Versions |
|---|---|---|
| dvankooten | MC4WP: Mailchimp for WordPress | 0 – through 4.12.0 |
Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
References
- https://www.wordfence.com/threat-intel/vulnerabilities/id/641b739d-f888-4327-b1c5-c95de39ee011?source=cve
- https://plugins.trac.wordpress.org/browser/mailchimp-for-wp/trunk/includes/forms/class-form.php#L295
- https://plugins.trac.wordpress.org/browser/mailchimp-for-wp/trunk/includes/forms/class-form-element.php#L116
- https://plugins.trac.wordpress.org/browser/mailchimp-for-wp/trunk/includes/forms/class-form-manager.php#L104
- https://plugins.trac.wordpress.org/changeset/3491781/