WordPress security changelog
HIGH CVE-2026-7520 Deferred

MailMunch subscriber relinking diverts captured subscribers and site forms

Mailmunch Forms for Mailchimp through 3.2.7 omits capability checks from the sign_in() and sign_up() AJAX handlers. A Subscriber can submit credentials for an attacker-controlled MailMunch account and relink the site's integration. Newly captured subscriber data is then delivered to the attacker, while forms and landing pages rendered on the WordPress site are loaded from the attacker's account. The CNA does not disclose the AJAX action or credential parameter names.

CVE / CNA score 8.1 CVSS 3.1 · security@wordfence.com
NVD score Pending NVD has not published its own CVSS assessment.
Component
Mailmunch Forms for Mailchimp
Plugin slug
mailchimp-forms-by-mailmunch
Affected
<= 3.2.7
Safe version
3.2.8
Published
Aug 05, 2026
Weakness
CWE-862 — Missing Authorization

This CVE was published Aug 05, 2026 and is one of 4 known issues for this plugin.

What to do

Update, patch or deactivate.

Update Mailmunch Forms for Mailchimp to 3.2.8 or later. The upstream changeset identifies 3.2.8 as the fixed tag. Verify the connected MailMunch account, audit Subscriber access and review forms, landing pages and captured subscriber destinations for unauthorized changes.

A safe version is available, so updating to that version or later is the preferred remediation. If an immediate update is not practical, consider a targeted application patch or temporarily restricting the affected functionality.

Deactivate only when warranted by your risk profile, or when advised by your hosting provider in the limited circumstances where the vulnerability cannot otherwise be mitigated. If you’re unsure which action is appropriate, contact Fused or your hosting provider for guidance.

Source record

Technical 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.

CVE / CNA vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

References

Primary and upstream sources