What’s Vulnerable › Vulnerabilities
CVE-2026-7520: MailChimp Forms by MailMunch <= 3.2.7 - Missing Authorization to Authenticated (Subscriber+) MailMunch Integration Takeover via 'sign_in' AJAX Action
- Severity: high (CVSS 8.1 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.5% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-08-05 · updated 2026-08-12
- Weakness: CWE-862
Description
The MailChimp Forms by MailMunch plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the `sign_in()` and `sign_up()` AJAX handlers in all versions up to, and including, 3.2.7. This makes it possible for authenticated attackers, with Subscriber-level access and above, to relink the site's MailMunch integration to an attacker-controlled MailMunch account by submitting attacker-supplied credentials. Once relinked, all subscriber data captured by the plugin's forms is delivered to the attacker, and the forms/landing pages rendered on the site are pulled from the attacker's MailMunch account.
Affected products
- Mailmunch Forms for Mailchimp: through 3.2.7
References
- https://plugins.trac.wordpress.org/browser/mailchimp-forms-by-mailmunch/tags/3.2.7/admin/class-mailchimp-mailmunch-admin.php#L126
- https://plugins.trac.wordpress.org/browser/mailchimp-forms-by-mailmunch/tags/3.2.7/admin/class-mailchimp-mailmunch-admin.php#L134
- https://plugins.trac.wordpress.org/browser/mailchimp-forms-by-mailmunch/tags/3.2.7/includes/class-mailchimp-mailmunch.php#L219
- https://plugins.trac.wordpress.org/browser/mailchimp-forms-by-mailmunch/tags/3.2.7/includes/class-mailmunch-api.php#L354
- https://plugins.trac.wordpress.org/browser/mailchimp-forms-by-mailmunch/tags/3.2.7/includes/class-mailmunch-api.php#L371
- https://plugins.trac.wordpress.org/browser/mailchimp-forms-by-mailmunch/trunk/admin/class-mailchimp-mailmunch-admin.php#L134
- https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&new=3593826%40mailchimp-forms-by-mailmunch%2Ftags%2F3.2.8&old=3445363%40mailchimp-forms-by-mailmunch%2Ftags%2F3.2.7
- https://www.wordfence.com/threat-intel/vulnerabilities/id/c9d00ee8-b9df-4044-a5e2-320391d6c9b1?source=cve
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