What the vulnerability does
01Description
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.
Explanation of Vulnerability in Simple Terms
02Summary
Mailmunch Forms for Mailchimp versions 3.2.7 and earlier lack proper authorization checks, allowing authenticated users to read and modify data they should not have access to. An attacker with a low-privilege account can view sensitive information and make unauthorized changes. Update to a version newer than 3.2.7 to resolve this issue.
What an attacker can do
03Attacker Capabilities
Read and modify sensitive data belonging to other users or the site.
Potential impact on your site
04Site Impact
User data and form submissions may be exposed or altered by unauthorized accounts.
Conditions required to exploit
05Prerequisites
Attacker must have a low-privilege account on the site; no user interaction required.
Key dates
06Disclosure timeline
August 5, 2026
CVE published
August 5, 2026
Record updated
