What is CVE-2023-40203?

CVE-2023-40203 is a medium-severity vulnerability in Mailmunch Mailchimp Forms, classified under Missing Authorization. CVSS score: 4.3/10. Published 2024-12-13.

How severe is CVE-2023-40203?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Is CVE-2023-40203 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Auth bypass in Mailmunch Mailchimp Forms

CVE-2023-40203

Missing Authorization vulnerability in MailMunch MailChimp Forms by MailMunch allows Exploiting Incorrectly Configured Access Control Security Levels.This issue affects MailChimp Forms by MailMunch: from n/a through 3.1.4.

Vulnerability class: Broken Access Control

Published 2024-12-13 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L.

EPSS exploit prediction

EPSS: 0.007 (51.5th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 52nd percentile — 51.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: +0.000

Affected products

Weakness classification (CWE)

CWE-862 — Missing Authorization

Public proof-of-concept exploits

20142995/nuclei-templates

References

patchstack.com/database/wordpress/plugin/mailchimp-forms-by-mailmunch/vulnerabi… (Third Party Advisory, vdb-entry)

Frequently asked questions

What is CVE-2023-40203?: CVE-2023-40203 is a medium-severity vulnerability in Mailmunch Mailchimp Forms, classified under Missing Authorization. CVSS score: 4.3/10. Published 2024-12-13.
How severe is CVE-2023-40203?: Medium severity. CVSS v3 base score is 4.3 out of 10.
Is CVE-2023-40203 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.