Known vulnerabilities in MC4WP: Mailchimp for WordPress

The #1 Mailchimp plugin for WordPress. Allows you to add a multitude of newsletter sign-up methods to your site.

12Reported vulnerabilities

8.8Highest CVSS score

4.14.0Latest version

1,000,000+Active installs

What to do now

Update MC4WP: Mailchimp for WordPress to 4.12.1 or later. 12 of these have a fixed version available. Updating resolves them.

Plugin last updated: August 4, 2026 / Tested up to WordPress: 7.0.4 / View on wordpress.org

Reported vulnerabilities

Ordered by how urgently they need attention — whether a vulnerability is actually being exploited, and how likely exploitation is, rather than CVSS severity alone.

CVE	Severity	Exploit probability next 30 days	Affected versions	Fixed in	Published
WF-370a6130-425c-4264-baaf-8989d3b00d14	High 8.8	—	4.8.4 and earlier	`4.8.5`	June 1, 2021
CVE-2026-4561	Medium 6.4	0.3%	0 to 4.12.0 (inclusive)	`4.12.1`	August 22, 2026
CVE-2026-1781	Medium 6.5	0.3%	0 to 4.11.1 (inclusive)	`4.12.0`	March 11, 2026
CVE-2017-18577	Medium 6.1	0.9%	Before 4.1.8	`4.1.8`	August 22, 2019
CVE-2016-10871	Medium 6.1	0.9%	Before 4.0.11	`4.0.11`	August 13, 2019
CVE-2024-8850	Medium 6.1	0.5%	4.9.9 to 4.9.16 (inclusive)	`4.9.17`	September 19, 2024
WF-dd7db465-ebeb-477b-b6c8-a9b89ba2372b	Medium 6.1	—	4.8.4 and earlier	`4.8.5`	June 1, 2021
WF-86cb08ae-aa21-4ee6-baed-03429e4d38e2	Medium 6.1	—	4.1.6 and earlier	`4.1.7`	November 9, 2019
CVE-2024-8680	Medium 5.5	0.5%	Before 4.9.17	`4.9.17`	September 21, 2024
WF-bd57edf5-a75e-4677-a51e-9dd262eeba4a	Medium 5.5	—	Before 4.8.7	`4.8.7`	March 2, 2022
CVE-2023-51682	Medium 5.3	0.4%	4.9.9 and earlier	`4.9.10`	December 27, 2023
CVE-2021-36833	Medium 4.8	0.5%	4.8.6 and earlier	`4.8.7`	May 20, 2022

Sources: vulnerability records from NVD, exploitation from CISA KEV, exploit probability from EPSS. Affected versions come from CPE ranges or from the reporting CNA.