CVE-2026-15052

HIGH

MailChimp Subscribe Form, Optin Builder, PopUp Builder, Form Builder <= 4.3.3 - Unauthenticated Stored Cross-Site Scripting via Form Field Values

Title source: cna

Description

The MailChimp Subscribe Form, Optin Builder, PopUp Builder, Form Builder plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Form Field Values in all versions up to, and including, 4.3.3 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

References (7)

Core 7

Core References

https://www.wordfence.com/threat-intel/vulnerabilities/id/c3d2425e-69e5-4efe-bbc6-0ef121e74341?source=cve

https://plugins.trac.wordpress.org/browser/mailchimp-subscribe-sm/tags/4.3.3/integrations/form-builder-database/extension.php#L179

https://plugins.trac.wordpress.org/browser/mailchimp-subscribe-sm/tags/4.3.3/integrations/form-builder-database/extension.php#L127

https://plugins.trac.wordpress.org/browser/mailchimp-subscribe-sm/tags/4.3.3/admin/classes/ajax-requests-class.php#L1224

https://plugins.trac.wordpress.org/browser/mailchimp-subscribe-sm/tags/4.3.3/admin/classes/ajax-requests-class.php#L2311

https://plugins.trac.wordpress.org/browser/mailchimp-subscribe-sm/tags/4.3.3/admin/classes/ajax-requests-class.php#L906

https://plugins.trac.wordpress.org/changeset?reponame=&old=3627272%40mailchimp-subscribe-sm&new=3627272%40mailchimp-subscribe-sm

Scores

CVSS v3 7.2

EPSS 0.0024

EPSS Percentile 15.3%

Attack Vector NETWORK

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

CISA SSVC

Vulnrichment

Exploitation none

Automatable yes

Technical Impact partial

Details

CWE

CWE-79

Status published

Products (1)

umarbajwa/MailChimp Subscribe Form, Optin Builder, PopUp Builder, Form Builder < 4.3.3

Published Aug 01, 2026

Tracked Since Aug 01, 2026