MailChimp Forms by MailMunch <= 3.2.7 - Missing Authorization to Authenticated (Subscriber+) MailMunch Integration Takeover via 'sign_in' AJAX Action
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 software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| WordPress plugin | Mailmunch Forms for Mailchimp | <= 3.2.7 | 3.2.8 |
References
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N- Weakness (CWE)
CWE-862- Platform
- WordPress
- Package
Mailmunch Forms for Mailchimp- Disclosed
- 04.08.2026
- Updated
- 11.10.2026 10:23
Sources and licenses
Wordfence Intelligence - c9d00ee8-b9df-4044-a5e2-320391d6c9b1 - Wordfence Intelligence
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Copyright 2012-2026 Defiant Inc.
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Vulnerability history: Mailmunch Forms for Mailchimp
All published vulnerabilities of this package (WordPress plugin), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 6
- First → latest
- 08.2023 08.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 1
- Medium 5
Disclosures per year
- 2023: 2
- 2024: 3
- 2025: 0
- 2026: 1
-
MailChimp Forms by MailMunch <= 3.2.7 - Missing Authorization to Authenticated (Subscriber+) MailMunch Integration Takeover via 'sign_in' AJAX Action this entry
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