What’s Vulnerable › Vulnerabilities

CVE-2026-4561: MC4WP: Mailchimp for WordPress <= 4.12.0 - Authenticated (Author+) Stored Cross-Site Scripting via Form Response Messages

• Severity: medium (CVSS 6.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-22 · updated 2026-10-12
• Weakness: CWE-79

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

• dvankooten MC4WP: Mailchimp for WordPress: through 4.12.0

References

• 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/browser/mailchimp-for-wp/trunk/includes/forms/class-form.php#L295
• https://plugins.trac.wordpress.org/changeset/3491781/
• https://www.wordfence.com/threat-intel/vulnerabilities/id/641b739d-f888-4327-b1c5-c95de39ee011?source=cve

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