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Cross-site Scripting (XSS)Weakness · CWE-79

CVE-2026-4067

MEDIUM · 6.4 CVSS v3.1 Published 2026-03-21
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
70/100
Remediation priority · Elevated
Remotely reachable Zero-click

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 Ad Short plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'ad' shortcode's 'client' attribute in all versions up to and including 2.0.1. This is due to insufficient input sanitization and output escaping on the 'client' shortcode attribute. The ad_func() shortcode handler at line 71 accepts a 'client' attribute via shortcode_atts() and directly concatenates it into a double-quoted HTML attribute (data-ad-client) at line 130 without applying esc_attr() or any other sanitization. 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 confidence

The Ad Short WordPress plugin (versions up to 2.0.1) is vulnerable to stored XSS via the 'client' attribute in the [ad] shortcode. The ad_func() handler accepts the client parameter and directly outputs it into a data-ad-client HTML attribute without sanitization (missing esc_attr()), allowing authenticated contributors+ to inject arbitrary JavaScript.

MitigationApply esc_attr() to the 'client' attribute before output in the ad_func() function at line 130, and update to version 2.0.2 or later when available.

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 checks

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

  1. Identify Ad Short plugin installation
    In WordPress admin, go to Plugins > Installed Plugins and look for 'Ad Short' or check the plugins directory (wp-content/plugins/ad-short/) for the plugin folder
    Affected if The Ad Short plugin is present in the WordPress installation
  2. Determine installed plugin version
    Check the plugin main PHP file header (usually ad-short.php in the plugin directory) for the 'Version' comment, or view the plugin details in WordPress admin Plugins page
    Affected if Version is 2.0.1 or lower (any version up to and including 2.0.1)
  3. Locate the vulnerable ad_func function
    Open the main plugin PHP file and search for the function named 'ad_func' or 'ad_shortcode', then locate where the 'client' parameter is handled around line 130
    Affected if The function exists and processes a 'client' parameter from shortcode attributes
  4. Check for missing esc_attr sanitization
    In the ad_func function, find where the client value is output into a data-ad-client HTML attribute (look for data-ad-client=), then verify whether esc_attr() is wrapped around the client value
    Affected if The client parameter is output directly without esc_attr() sanitization (e.g., data-ad-client="$client" instead of data-ad-client="esc_attr($client)")
  5. Detect if vulnerable shortcodes are in use
    Search WordPress database (wp_posts table) or content files for [ad shortcode usage with a client attribute, e.g., [ad client="..."]
    Affected if Any [ad] shortcode with a client attribute exists in posts, pages, or widgets
  6. Check for contributor-level or higher user accounts
    Review WordPress user roles at Users > All Users to identify any users with Contributor, Author, Editor, or Administrator roles
    Affected if Users with Contributor or higher privileges exist who could create or edit content containing the malicious shortcode

The environment is affected if the Ad Short plugin version 2.0.1 or lower is installed AND the client attribute in [ad] shortcodes is output without esc_attr() sanitization in the ad_func function, allowing stored XSS injection by authenticated users with Contributor access or higher.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply esc_attr() to the 'client' attribute before output in the ad_func() function at line 130, and update to version 2.0.2 or later when available.

Recommended fix Moderate confidence

Ad Short plugin version 2.0.2 or latest available version

  1. 1. Navigate to the WordPress admin dashboard
  2. 2. Go to Plugins > Installed Plugins
  3. 3. Locate the 'Ad Short' plugin
  4. 4. If an update is available, click 'Update Now' to install the latest version
  5. 5. After updating, verify the 'client' attribute in any 'ad' shortcodes uses properly sanitized values or remove/regenerate shortcodes that may have been injected with malicious scripts

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

Have this fixed Scoped from the published advisory
  • Consultation1.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
5.0 hours of engineering $860
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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-2026-4067 in production — separate from our analysis above.

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What this is

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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