QwikSec

Security Database

CVE

CWE

Training

CVE Database
/

CVE-2026-1781

Back to search

CVE-2026-1781

Published: Mar 11, 2026

Modified: Apr 8, 2026

PUBLISHED

CVSS v3.1

6.5

MEDIUM

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).

VendorProductVersions

dvankooten

MC4WP: Mailchimp for WordPress

affected
0 - <= 4.11.1

Weaknesses (CWE)

CWE-862

CVSS v3.1 Details

CVSS v3.1 Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

Low

Availability

Low

References

Security Training

Train your team to recognize and prevent security threats with our comprehensive security awareness program.

Start Training

Vulnerability Scanning

Discover vulnerabilities in your applications and infrastructure before attackers do.

Scan Now