CVE-2026-8868
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 Single Mailchimp plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'single-mailchimp' shortcode in all versions up to, and including, 1.4. This is due to insufficient input sanitization and output escaping on user-supplied shortcode attributes (autocomplete, label, placeholder, btn_text, success_msg, error_msg) which are concatenated directly into HTML output by the single_mailchimp() function in shortcodes.php. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.
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 Single Mailchimp WordPress plugin fails to sanitize or escape shortcode attributes (autocomplete, label, placeholder, btn_text, success_msg, error_msg) before outputting them in HTML. The single_mailchimp() function in shortcodes.php directly concatenates these user-supplied values into the page output, allowing stored XSS injection by any authenticated contributor or higher.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
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
- Low
- User interaction
- None
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/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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Confirm Single Mailchimp plugin is installedLog in to WordPress admin, go to Plugins > Installed Plugins, and look for 'Single Mailchimp' in the listAffected if the plugin is present in the WordPress installation
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Identify the installed plugin versionIn the Plugins list, click on the plugin name or view details to find the version number displayedAffected if the version cannot be determined or matches the vulnerable release
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Locate the shortcode fileAccess the WordPress file system and navigate to wp-content/plugins/single-mailchimp/shortcodes.phpAffected if the file exists and contains the single_mailchimp() function
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Verify shortcode is in useSearch WordPress posts, pages, or widgets for the [single_mailchimp] shortcodeAffected if the shortcode is present in any published content
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Inspect the vulnerable functionOpen shortcodes.php and locate the single_mailchimp() function, then check if attributes (autocomplete, label, placeholder, btn_text, success_msg, error_msg) are output without escapingAffected if the attributes are directly concatenated into HTML output without esc_attr() or similar escaping
A user is affected if the Single Mailchimp plugin is installed, the shortcode is used on the site, and the shortcode.php file shows the vulnerable attributes are output without proper escaping.
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 dataAdd proper input sanitization (esc_attr()) and output escaping to all shortcode attribute outputs in the single_mailchimp() function to prevent script injection.
- Consultation2.0 h
- Implementation3.0 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 $2,272.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-8868 — 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-2026-8868 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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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.
- 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