CVE intelligence and bounded remediation

CVE-2026-3481 — WP Blockade security vulnerability

Medium CVSS 6.1

The WP Blockade plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the 'shortcode' parameter in all versions up to and including 0.9.14. This is due to insufficient input sanitization and output escaping in the render_shortcode_preview() function. The function receives user input from $_GET['shortcode'], passes it through stripslashes() without any sanitization, and then outputs it directly via echo do_shortcode($shortcode) on line 393. When the input is not a valid WordPress shortcode (e.g., an HTML tag with JavaScript event handlers), do_shortcode() returns it unchanged, and it is reflected into the page without escaping. The endpoint is registered via admin_post_ (not admin_post_nopriv_), meaning it requires the user to be logged in with at minimum a Subscriber-level account. There is no nonce verification or additional capability check. This makes it possible for authenticated attackers, with Subscriber-level access and above, to inject arbitrary web scripts in pages that will execute if they can successfully trick a user into performing an action such as clicking a link.

Severity
Medium
CVSS
6.1 (3.1)
Published
2026-05-22
CISA KEV
Not currently listed
Ecosystem
php/wordpress
Weaknesses
CWE-79

Affected products

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Matched remediation archetype

Cross-site scripting and unsafe browser output

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Check exposure

  • Trace reflected, stored, and DOM-derived untrusted values into HTML, attributes, URLs, styles, scripts, and client-side template sinks.
  • Identify affected origins, authenticated user roles, sensitive browser capabilities, and where content is shared across tenants.
  • Review framework escaping, rich-text sanitization, legacy templates, and client-side rendering paths.

Remediate safely

  • Use context-aware framework output encoding and safe DOM APIs; keep untrusted data out of executable contexts.
  • Sanitize intentionally supported markup with a maintained allowlist policy and validate URLs and attributes separately.
  • Update affected rendering components and add tests for every output context using inert sentinel markup.

Authoritative sources

Complete CVE record and remediation plan

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