MC4WP: Mailchimp for WordPress <= 4.8.6 - Authenticated (Admin+) Stored Cross-Site Scripting

5.5
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVE CVE-2021-36833
CVSS 5.5 (Medium)
Publicly Published March 2, 2022
Last Updated January 22, 2024
Researcher Asif Nawaz Minhas - Patchstack Alliance

Description

The MC4WP: Mailchimp for WordPress plugin for WordPress is vulnerable to Stored Cross-Site Scripting via several parameters in versions up to, and including, 4.8.6 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers with administrative level permissions and above to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This only affects multi-site installations and installations where unfiltered_html has been disabled.

Learn more about Cross-Site Scripting vulnerabilities and how to prevent them.

References

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Vulnerability Details for MC4WP: Mailchimp for WordPress

Software Type Plugin
Software Slug mailchimp-for-wp (view on wordpress.org)
Patched? Yes
Remediation Update to version 4.8.7, or a newer patched version
Affected Version
  • <= 4.8.6
Patched Version
  • 4.8.7

Recent vulnerabilities in MC4WP: Mailchimp for WordPress

# Title CVE ID CVSS Researchers Date
1 MC4WP: Mailchimp for WordPress <= 4.12.0 - Authenticated (Author+) Stored Cross-Site Scripting via Form Response Messages CVE-2026-4561 6.4 Osvaldo Noe Gonzalez Del Rio (Os) August 21, 2026
2 MC4WP: Mailchimp for WordPress <= 4.11.1 - Missing Authorization to Unauthenticated Arbitrary Subscription Deletion CVE-2026-1781 6.5 Sarawut Poolkhet (MisterHelloz) March 10, 2026
3 MailChimp for Wordpress <= 4.9.16 - Authenticated (Administrator+) Stored Cross-Site Scripting CVE-2024-8680 4.4 Jorge Diaz (ddiax) September 20, 2024
4 MC4WP: Mailchimp for WordPress 4.9.9 - 4.9.16 - Reflected Cross-Site Scripting CVE-2024-8850 6.1 kauenavarro September 18, 2024
5 MC4WP <= 4.9.9 - Missing Authorization via listen CVE-2023-51682 5.3 Rafie Muhammad December 27, 2023
6 MC4WP: Mailchimp for WordPress < 4.8.7 - Cross-Site Scripting 5.5 March 2, 2022
7 MC4WP: Mailchimp for WordPress <= 4.8.4 - Cross-Site Request Forgery 8.8 WPScanTeam June 1, 2021
8 MC4WP: Mailchimp for WordPress <= 4.8.4 - Open Redirect 6.1 WPScanTeam June 1, 2021
9 MC4WP: Mailchimp for WordPress <= 4.1.6 - Reflected Cross-Site Scripting 6.1 RIPS Technologies November 9, 2019
10 Mailchimp For WP <= 4.1.7 - Cross-Site Scripting CVE-2017-18577 6.1 September 8, 2017

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