dbcve.org
Mailchimp FormsWordPress extension · Mailmunch

CVE-2023-40203

HIGH · 8.8 CVSS v3.1 Published 2024-12-13
Fix available
A fix is available. Upgrade to 3.1.5 or later.
See remediation →
95/100
Remediation priority · Urgent
Remotely reachable No privileges

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

Missing Authorization vulnerability in the MailMunch MailChimp Forms WordPress plugin allows attackers to exploit incorrectly configured access control security levels. The plugin fails to properly enforce authorization checks on certain actions, likely allowing lower-privileged users (or unauthenticated actors) to access functionality intended for higher-privileged users. This is a broken access control vulnerability where permission checks are either missing or improperly implemented.

MitigationUpdate the MailMunch MailChimp Forms plugin to the latest version (3.1.5 or later) which should contain proper authorization checks. Conduct a code audit of all admin and user-facing actions to ensure capability checks are consistently applied before sensitive operations.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Mailchimp FormsWordPress extension
Affected:< 3.1.5

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check installed plugin version
    In WordPress admin, go to Plugins > Installed Plugins > MailMunch MailChimp Forms and view the Version number. Alternatively, check the plugin header in /wp-content/plugins/mailmunch-mailchimp-forms/ or /wp-content/plugins/mailmunch/ directory for the 'Version:' tag.
    Affected if Version is less than 3.1.5 or the version number cannot be determined (plugin may be outdated or from a compromised source).
  2. Review user roles with administrative access
    Go to WordPress Users > All Users and list all users with Administrator or Editor roles. Cross-reference with who actually needs that access.
    Affected if Unknown or unexpected users have administrative capabilities, suggesting potential privilege escalation via the vulnerability.
  3. Inspect plugin capabilities configuration
    If you have code access, examine the plugin's main PHP files for add_action or add_filter calls that register AJAX handlers or admin actions. Look for missing capability checks (missing current_user_can() calls before sensitive operations).
    Affected if AJAX endpoints or admin actions lack current_user_can() or similar authorization checks before executing.
  4. Audit plugin settings for unauthorized modifications
    Review the MailMunch plugin settings in WordPress admin (MailMunch > Settings or similar) for any unexpected changes to API keys, form configurations, or audience settings that lower-privileged users may have modified.
    Affected if Settings show changes made by users who should not have permission to modify MailChimp integrations.

You are affected if the MailMunch MailChimp Forms plugin version is below 3.1.5 AND there is any possibility that untrusted users have access to your WordPress site, as the missing authorization could allow privilege escalation.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 3.1.5 or later
Fixed in 3.1.5
Interim mitigation

Update the MailMunch MailChimp Forms plugin to the latest version (3.1.5 or later) which should contain proper authorization checks. Conduct a code audit of all admin and user-facing actions to ensure capability checks are consistently applied before sensitive operations.

Recommended fix High confidence

3.1.5

  1. 1. Update the MailMunch MailChimp Forms plugin to version 3.1.5 or later
  2. 2. Verify the update was successfully applied by checking the plugin version
  3. 3. Test the plugin functionality to ensure the authorization controls are working properly

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Mailchimp Forms Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,088.

Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-40203 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data