MailChimp Subscribe Forms <= 4.0.9.3 - Open Redirect
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.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| WordPress plugin | MailChimp Subscribe Form, Optin Builder, PopUp Builder, Form Builder | <= 4.0.9.3 | 4.0.9.4 |
References
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N- Weakness (CWE)
CWE-601- Platform
- WordPress
- Package
MailChimp Subscribe Form, Optin Builder, PopUp Builder, Form Builder- Disclosed
- 10.05.2023
- Updated
- 11.10.2026 10:23
Sources and licenses
Wordfence Intelligence - aba1ca3a-a937-400b-b175-2ca4e67a107d - Wordfence Intelligence
Copyright 1999-2026 The MITRE Corporation
Copyright 2012-2026 Defiant Inc.
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Vulnerability history: MailChimp Subscribe Form, Optin Builder, PopUp Builder, Form Builder
All published vulnerabilities of this package (WordPress plugin), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 7
- First → latest
- 04.2015 08.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 3
- Medium 4
Disclosures per year
- 2017: 0
- 2018: 0
- 2019: 0
- 2020: 0
- 2021: 0
- 2022: 0
- 2023: 2
- 2024: 1
- 2025: 1
- 2026: 2
earlier: 1
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MailChimp Subscribe Forms <= 4.0.9.3 - Open Redirect this entry
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