Mailchimp For WordpressWordPress extension · Ibericode
CVE-2017-18577
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 · uneditedThe mailchimp-for-wp plugin before 4.1.8 for WordPress has XSS via the return value of add_query_arg.
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 confidenceThe MailChimp for WordPress plugin before version 4.1.8 contains a Cross-Site Scripting (XSS) vulnerability due to improper handling of the add_query_arg() function return value. When URLs generated by add_query_arg() are output to HTML without proper escaping (using esc_url() or esc_attr()), malicious JavaScript can be injected via crafted query parameters.
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 For WordpressWordPress extension
< 4.1.8CVSS 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:3.0/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 checksWork through these to decide whether this CVE applies to you.
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Locate the MailChimp for WordPress pluginAccess your WordPress site's wp-content/plugins/ directory and identify the plugin folder - typically named 'mailchimp-for-wp' or similar. Check the main plugin PHP file (usually mailchimp-for-wp.php or index.php) and look for the 'Version:' header in the plugin file comments to find the installed version number.Affected if The plugin is installed and the version listed is below 4.1.8
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Compare installed version to the affected rangeExamine the version number found in the plugin header. The affected versions are any release older than version 4.1.8, such as 4.1.7, 4.1.6, 4.1.5, 4.1.0, or earlier major versions.Affected if The installed version number is less than 4.1.8 (for example, 4.1.7, 4.0.0, or any version below 4.1.8)
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Identify the vulnerable add_query_arg patternsSearch the plugin PHP files for instances of 'add_query_arg' that are followed by output functions without proper escaping. Look for patterns like 'echo add_query_arg(' or 'href="add_query_arg(' where esc_url() or esc_attr() is NOT used on the add_query_arg return value.Affected if The plugin code contains add_query_arg() calls that output directly to HTML without being wrapped in esc_url() or esc_attr() functions, allowing crafted URL parameters to inject malicious JavaScript
You are affected if the MailChimp for WordPress plugin is installed with a version number below 4.1.8 AND your site outputs add_query_arg() return values in HTML contexts without escaping functions.
Generated from the published advisory. Verify against your own configuration.
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.
From vendor data4.1.8
Update the mailchimp-for-wp plugin to version 4.1.8 or later. In the meantime, implement output escaping using esc_url() or esc_attr() on all add_query_arg() return values before outputting them in HTML contexts.
Fix this in Mailchimp For Wordpress
Scoped from the published advisory
- Consultation2.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,984.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-18577 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2017-18577 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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