WP Blockade <= 0.9.14 - Reflected Cross-Site Scripting via 'shortcode' Parameter
Strategic Overview
- Status
- Unpatched
- Affected Plugin
- WP Blockade – Visual Page Builder
- Affected Version
<= 0.9.14- CVSS
- 6.1Medium
- Weakness type
- CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
- CVE
CVE-2026-3481
At a glance
CVE-2026-3481 is a medium-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the WP Blockade WordPress plugin, affecting versions <= 0.9.14. It carries a CVSS score of 6.1 (reachable over the network; low attack complexity). Exploitation requires no authentication. No fixed release has been reported yet; treat installations running this software as exposed. Disclosed May 2026, reported by theviper17y.
Vulnerability Overview
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.
Technical Analysis
The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site.
CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
WP Blockade <= 0.9.14 carries this weakness at shortcode, and reaching it takes a caller who can reach the endpoint. Cross-site scripting happens when input from a request is written into a page without being escaped for the context it lands in, so the browser parses attacker-supplied text as markup or script.
Injected script runs with the privileges of whoever views the affected page, which is how these flaws turn into administrator session theft, silent account creation or persistent backdoors in page content. No fixed build of this plugin is recorded for WP Blockade yet, so installs running <= 0.9.14 stay exposed until the vendor ships one.
Remediation
No known patch available. Please review the vulnerability's details in depth and employ mitigations based on your organization's risk tolerance. It may be best to uninstall the affected software and find a replacement.
How does WordSec protect against this?
The attempt arrives as an ordinary request to WP Blockade: WordSec's web application firewall inspects request payloads before WordPress loads them. No patched version is recorded yet, which is the case where a filtering layer matters most, because there is nothing to update to.
- Firewall
- Alerts
External References
Related records
Other vulnerabilities in WP Blockade – Visual Page Builder
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