ZDF
Sign inSign up

Vulnerabilities

Vulnerability · CVE-2026-1781

The MC4WP: Mailchimp for WordPress plugin for WordPress is vulnerable to Missing Authorization in all versions up to, and including, 4.11.1.

Published Mar 11, 2026 · catalog updated Jun 17, 2026 · The MC4WP: Mailchimp for

Check if you run it

No confirmed exploitation is on record for CVE-2026-1781. EPSS is 0.28%. Act only if a listed version of The MC4WP: Mailchimp for is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (The MC4WP: Mailchimp for).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium6.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.28%
Remediation
Version ranges on file
Affected products
stated named in the record

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 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 parameter, granted they can obtain the form ID (which is publicly exposed in the HTML source).

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • stated named in the record<= 4.11.1

How to fix CVE-2026-1781

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-1781. EPSS is 0.28%. Act only if a listed version of The MC4WP: Mailchimp for is installed.

Which versions are affected?

Compare what you have installed with named in the record <= 4.11.1. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-862: Missing Authorization. EPSS 0.28%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

WordPress security

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Mar 11, 2026 · NIST NVD

    Detected

    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 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 uns

  2. Jun 17, 2026 · NIST NVD

    Updated

    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 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 uns

Sources

  • CVE.orgVulnerability recordCVE-2026-1781

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-1781

    30-day exploitation probability 0.3%

    first.org
  • NIST NVDVulnerability recordCVE-2026-1781

    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 POST parameter without validation, allowing unauthenticated attackers to force the f

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.