Threat intelligence

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

CVE-2026-27536 · mailchimp-subscribe-sm

Important: Seeing this vulnerability listed does not mean your website is affected. Exposure depends on whether you run Mailchimp Subscribe Sm at a vulnerable version. How SiteRespond intelligence works

Vulnerability: MailChimp Subscribe Form, Optin Builder, PopUp Builder, Form Builder <= 4.3.3 - Unauthenticated Stored Cross-Site Scripting
Affected software: mailchimp-subscribe-sm(Plugin)
Affected versions: ≤ 4.3.3
Authentication: Unauthenticated
Vulnerability type: Cross-site scripting
CVE: CVE-2026-27536
Published: 11 August 2026
CISA KEV: Not listed in CISA KEV at last catalog refresh
Impact: May allow attackers to run scripts in visitors' browsers or hijack admin sessions.
Source: Data imported from Wordfence Intelligence (advisory cd02c709-f0c0-43cc-b0b5-90b8cb1837fe). Methodology and redistribution notes

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