CVE-2026-4081
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 ZeM STL plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the [zemstl] shortcode in all versions up to and including 1.0. This is due to insufficient input sanitization and output escaping on user-supplied shortcode attributes, specifically the 'url', 'color', and 'bgcolor' parameters. These attribute values are directly interpolated into HTML attribute context without being passed through esc_attr() or any other escaping function. 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 ZeM STL WordPress plugin fails to escape shortcode attribute values ('url', 'color', 'bgcolor') before outputting them in HTML attributes, allowing authenticated attackers with Contributor+ privileges to inject arbitrary JavaScript via the [zemstl] shortcode.
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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Verify ZeM STL plugin is installedIn WordPress admin, go to Plugins > Installed Plugins and look for 'ZeM STL' or 'Zem STL' plugin. Alternatively, check the /wp-content/plugins/ directory for a folder containing 'zem' or 'stl' in the name.Affected if The plugin is installed and active
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Determine the installed plugin versionIn WordPress admin > Plugins, click on the ZeM STL plugin to view its details, or inspect the plugin's main PHP file for a 'Version' header comment.Affected if The installed version is older than any patched version released for this CVE (compare your version to the vendor's advisory)
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Confirm the shortcode is accessibleTest if the [zemstl] shortcode is registered by creating a test post with [zemstl] and viewing it, or inspect the plugin code for add_shortcode('zemstl', ...)Affected if The [zemstl] shortcode is registered and accessible to users with Contributor-level access or higher
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Check user role permissions for shortcode usageIn WordPress admin > Users, verify which roles have access to create/edit posts containing shortcodes. Contributor role can create posts but requires approval for publication.Affected if Users with Contributor role or higher can access the shortcode without additional restrictions
You are affected if the ZeM STL plugin is installed, the [zemstl] shortcode is accessible, and untrusted users (such as Contributors) can use the shortcode to inject malicious attribute values.
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 esc_attr() escaping to all shortcode attribute outputs in the plugin's shortcode handler, and implement input validation/sanitization on the 'url', 'color', and 'bgcolor' parameters.
- Consultation1.0 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 $1,664.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-4081 — 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-2026-4081 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
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