CVE-2026-1781

6.5 MEDIUM
Published: March 11, 2026 Modified: March 11, 2026
View on NVD

Description

The MC4WP: Mailchimp for WordPress plugin for WordPress is vulnerable to Missing Authorization in all versions up to, and including, 4.11.1. This is due to the plugin trusting the `_mc4wp_action` POST parameter without validation, allowing unauthenticated attackers to force the form to process unsubscribe actions instead of subscribe actions. This makes it possible for unauthenticated attackers to arbitrarily unsubscribe any email address from the connected Mailchimp audience via the `_mc4wp_action` parameter, granted they can obtain the form ID (which is publicly exposed in the HTML source).

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L

Quick Stats

CVSS v3 Score
6.5 / 10.0
EPSS (Exploit Probability)
0.1%
15th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)