dbcve.org
Mailchimp Top BarWordPress extension · Ibericode

CVE-2024-9210

MEDIUM · 6.1 CVSS v3.1 Published 2024-10-02
Fix available
A fix is available. Upgrade to 1.6.1 or later.
See remediation →
68/100
Remediation priority · Elevated
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
The MC4WP: Mailchimp Top Bar plugin for WordPress is vulnerable to Reflected Cross-Site Scripting due to the use of add_query_arg without appropriate escaping on the URL in all versions up to, and including, 1.6.0. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a link.

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 · high confidence

The Mailchimp Top Bar WordPress plugin versions up to 1.6.0 contains a reflected cross-site scripting vulnerability. The plugin uses the WordPress add_query_arg function to manipulate URLs but fails to properly escape the resulting URL output before rendering it, allowing attacker-controlled JavaScript to be executed in a victim's browser via malicious links.

MitigationUpgrade the Mailchimp Top Bar plugin to version 1.6.1 or later. Until patched, users should avoid clicking untrusted links that reference sites running this plugin.

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 Top BarWordPress extension
Affected:< 1.6.1

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
Changed
Confidentiality
Low
Integrity
Low
Availability
None

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

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 > Mailchimp Top Bar. The version number is displayed below the plugin name. Alternatively, check the plugin header in wp-content/plugins/mailchimp-top-bar/mailchimp-top-bar.php for 'Version:' value.
    Affected if Version is 1.6.0 or lower (any version below 1.6.1)
  2. Verify plugin is active
    In WordPress admin, go to Plugins > Installed Plugins and confirm the Mailchimp Top Bar plugin shows 'Active' status under the plugin name.
    Affected if Plugin is active and version is vulnerable (below 1.6.1)
  3. Identify usage of add_query_arg in plugin
    Review the plugin PHP files, particularly files handling form submissions or redirects. Search for 'add_query_arg' function calls that are not followed by esc_url or esc_attr before output.
    Affected if add_query_arg is used without proper escaping on URL parameters that could be user-controlled
  4. Check for exposed query string parameters
    Test the frontend pages where the plugin is active by adding query parameters (e.g., ?mc_sub=TEST) to the URL and checking if they reflect in the page output without proper encoding.
    Affected if Query parameters from add_query_arg reflect in page output unescaped, allowing script injection via malicious links

A user is affected if the Mailchimp Top Bar plugin is installed, active, and running version 1.6.0 or lower, as the reflected XSS vulnerability exists in how the plugin handles URL parameters.

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 1.6.1 or later
Fixed in 1.6.1
Interim mitigation

Upgrade the Mailchimp Top Bar plugin to version 1.6.1 or later. Until patched, users should avoid clicking untrusted links that reference sites running this plugin.

Recommended fix High confidence

Mailchimp Top Bar version 1.6.1

  1. Log in to your WordPress admin dashboard
  2. Navigate to Plugins > Installed Plugins
  3. Find the 'MC4WP: Mailchimp Top Bar' plugin
  4. Click 'Update now' if an update is available, or manually update to version 1.6.1
  5. Verify the plugin version shows 1.6.1 after updating

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

Fix this in Mailchimp Top Bar Scoped from the published advisory
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing3.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,210
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,936.

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-2024-9210 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