CVE-2026-27536Network attack vector

Unauthenticated script execution in visitor browsers

Published Aug 13, 2026 · Updated Aug 13, 2026

Cross-site scripting in PluginOps MailChimp Subscribe Forms 4.3.3 and earlier allows remote attackers to run scripts in visitor browsers. Published advisories identify neither the affected input nor the plugin code path that accepts and renders it without adequate neutralization. Exploitation requires no account but requires a user to visit content carrying the payload; execution remains within that browser context.

CVSS severity7.1
High
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in PluginOps MailChimp Subscribe Forms 4.3.3 and earlier allows remote attackers to run scripts in visitor browsers. Published advisories identify neither the affected input nor the plugin code path that accepts and renders it without adequate neutralization. Exploitation requires no account but requires a user to visit content carrying the payload; execution remains within that browser context.

The record

CVE
CVE-2026-27536
Published
Aug 13, 2026
Updated
Aug 13, 2026
Vendor
PluginOps
Product
MailChimp Subscribe Form, Optin Builder, PopUp Builder, Form Builder
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 13, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 13, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=n/a <=4.3.3 changes=[{"at":"4.3.4","status":"unaffected"}]

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

PluginOps · MailChimp Subscribe Form, Optin Builder, PopUp Builder, Form Builderversion=n/a <=4.3.3 changes=[{"at":"4.3.4","status":"unaffected"}]

Published CVSS scores

7.1INCIBE-CERTCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007JavaScript/JScript

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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