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Vulnerability · Published Aug 1, 2026 · Assigned by Wordfence

CVE-2026-15052MailChimp Subscribe Form, Optin Builder, PopUp Builder, Form Builder <= 4.3.3 - Unauthenticated Stored Cross-Site Scripting via Form Field Values

High 7.2

In plain English

A high-severity cross-site scripting in MailChimp Subscribe Form, Optin Builder, PopUp Builder, Form Builder from umarbajwa. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 36% of all known vulnerabilities).

Severity (CVSS 3.1)7.2High
Exploit odds (30 days)0.4%top 63.6% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

VendorProductVersions
umarbajwa MailChimp Subscribe Form, Optin Builder, PopUp Builder, Form Builder 0 – through 4.3.3

Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

References