Missing authorization in Mailmunch Forms for Mailchimp
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- High · High · None
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-862.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2026-7520
- 2026-10-03 Alias added: GHSA-49m8-524g-8rr2
References
Other 8
- https://www.wordfence.com/threat-intel/vulnerabilities/id/c9d00ee8-b9df-4044-a5e2-320391d6c9b1?source=cve
- https://plugins.trac.wordpress.org/browser/mailchimp-forms-by-mailmunch/trunk/admin/class-mailchimp-mailmunch-admin.php#L134
- 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/admin/class-mailchimp-mailmunch-admin.php#L126
- 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/tags/3.2.7/includes/class-mailchimp-mailmunch.php#L219
- 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
More MailMunch vulnerabilities
- TI-2023-21073 WordPress MailChimp Forms by MailMunch plugin <= 3.1.4 - Broken Access Control CVSS 3.1HIGH 8.8
- TI-2023-24522 WordPress MailChimp Forms by MailMunch Plugin <= 3.1.4 is vulnerable to Cross Site Request Forgery (CSRF) CVSS 3.1HIGH 8.8
- TI-2023-24448 WordPress Constant Contact Forms by MailMunch Plugin <= 2.0.10 is vulnerable to Cross Site Request Forgery (CSRF) CVSS 3.1HIGH 8.8
- TI-2023-22245 WordPress MailMunch – Grow your Email List Plugin <= 3.1.2 is vulnerable to Cross Site Request Forgery (CSRF) CVSS 3.1HIGH 8.8
- TI-2024-20750 WordPress MailChimp Forms by MailMunch plugin <= 3.2.1 - Cross Site Request Forgery (CSRF) vulnerability CVSS 3.1HIGH 8.8
- TI-2026-56419 WordPress MailMunch – Grow your Email List plugin <= 3.2.5 - Broken Authentication vulnerability CVSS 3.1HIGH 7.1
Sources
- CVE-2026-7520 · CVE Program
- CVE-2026-7520 · NVD
- FIRST EPSS
- GHSA-49m8-524g-8rr2 · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences