VulnCrest
Search
Create account
Report an incident
Radar sectionsDatabase
Check my site
WordPress plugin

MailChimp Subscribe Forms <= 4.0.9.3 — Open Redirect

CVE-2023-32517Published · Updated

Action summary

Affected: ≤4.0.9.3Update to 4.0.9.4 or newer

All remediation steps
Watch plugin
Severity
Medium6.1
CVSS
6.1
CVSS 3.1 · CNA (Wordfence)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
What does this vector mean?
AV:N Attack vector
Network
AC:L Attack complexity
Low
PR:N Privileges required
None
UI:R User interaction
Required
S:C Scope
Changed
C:L Confidentiality
Low
I:L Integrity
Low
A:N Availability
None
Weakness
CWE-601 Open Redirect
Required access
No account needed
Exploit prediction (EPSS)
No score
CISA KEV
Not listed
On this page8

Am I affected?

MailChimp Subscribe Form, Optin Builder, PopUp Builder, Form Builder mailchimp-subscribe-sm

  1. Affected≤ 4.0.9.3
  2. Patched in4.0.9.4

Update to 4.0.9.4 or newer.

You are affected if you run ≤ 4.0.9.3. Version 4.0.9.4 and later are not affected by this issue.

  • Check your version: in wp-admin go to Plugins → Installed Plugins and read the version under MailChimp Subscribe Form, Optin Builder, PopUp Builder, Form Builder.
  • No admin access? Run a passive check of your site. It reads public files only.
  • No account is needed to exploit this. Treat any exposed site on an affected version as at risk.

What to do

  1. Update to version 4.0.9.4, or a newer patched version
  2. Rotate administrator passwords and application secrets if the site ran a vulnerable version while publicly reachable.
  3. Watch MailChimp Subscribe Form, Optin Builder, PopUp Builder, Form Builder to get an email when the next vulnerability is published.

Advisory

Source description from Wordfence Intelligence, credited to minhtuanact.

The MailChimp Subscribe Forms plugin for WordPress is vulnerable to Open Redirect in versions up to, and including, 4.0.9.3. This is due to the application failing to properly verify a user-supplied input parameter. This makes it possible for unauthenticated attackers to exploit this issue and redirect users to arbitrary web sites and conduct phishing attacks; other attacks are also possible.

Exploits & references

Proof-of-concept & detection

No public proof-of-concept or detection template is known for this vulnerability.

Advisories & patches

More in MailChimp Subscribe Form, Optin Builder, PopUp Builder, Form Builder

All 7
More vulnerabilities in MailChimp Subscribe Form, Optin Builder, PopUp Builder, Form Builder
SeverityVulnerabilityCVEPublished
High7.2Unauthenticated Stored Cross-Site Scripting
≤4.3.3Update to 4.3.4
CVE-2026-27536
High7.2Unauthenticated Stored Cross-Site Scripting via Form Field Values
≤4.3.3Update to 4.3.4
CVE-2026-15052
Medium6.4Authenticated (Contributor+) Stored Cross-Site Scripting
≤4.1Update to 4.2
CVE-2025-22727
Medium4.4Authenticated (Editor+) Stored Cross-Site Scripting
≤4.0.9.7Update to 4.0.9.8
CVE-2024-43211
Medium4.4Authenticated (Administrator+) Stored Cross-Site Scripting
≤4.0.9.1Update to 4.0.9.2
CVE-2023-33328

Same weakness (Open Redirect)

All Open Redirect
Other Open Redirect vulnerabilities
SeverityVulnerabilityCVEPublished
High7.2Unauthenticated Stored Cross-Site Scripting via Comment User-Agent Header
EZ SQL Reports Shortcode Widget and DB Backup≤5.25.25Update to 5.26.45
CVE-2026-120688
Critical9.8Unauthenticated Arbitrary File Upload via File Upload via Public Form Submission
Chatterbug Forms – Fast, Flexible WordPress Form Builder≤1.0.2Update to 1.1
CVE-2026-125055
Critical9.8Unauthenticated PHP Object Injection to Remote Code Execution via 'form' Parameter
ELEX WordPress HelpDesk & Customer Ticketing System≤3.3.9Update to 3.4.0
CVE-2026-119077
Medium5.3Unauthenticated Sensitive Information Exposure in 'search' Parameter
Customer Reviews for WooCommerce≤5.127.0Update to 5.128.0
CVE-2026-121518

Timeline

  1. CVE published

    Severity medium, CVSS 6.1

  2. Record last updated

Sources & licenses

Wordfence record
Vulnerability data
Wordfence Intelligence. Copyright 2012-2026 Defiant Inc. Licensed under the CC BY-SA 4.0.
CVE® identifiers
Copyright 1999-2026 The MITRE Corporation. Used under the CVE Program. CVE® is a registered trademark of The MITRE Corporation.
CVSS / CWE
National Vulnerability Database (NVD), shown unmodified. This product uses the NVD API but is not endorsed or certified by the NVD.
VulnCrest content
Summary, remediation guidance and page layout © VulnCrest. Not sourced from NVD.

How we use these sources

Search VulnCrest Radar

Jump to

Are you sure?