CVE-2026-3481

Description

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.

Predictions

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

References

• https://plugins.trac.wordpress.org/browser/wp-blockade/tags/0.9.14/wp-blockade.php#L360
• https://plugins.trac.wordpress.org/browser/wp-blockade/tags/0.9.14/wp-blockade.php#L393
• https://plugins.trac.wordpress.org/browser/wp-blockade/trunk/wp-blockade.php#L360
• https://plugins.trac.wordpress.org/browser/wp-blockade/trunk/wp-blockade.php#L393
• https://www.wordfence.com/threat-intel/vulnerabilities/id/66950509-ce2a-42fe-a8b2-2a92a1b573c3?source=cve

CWEs

CWE-79