WP-Safety
CVE-2026-6237

Quick Table <= 1.0.0 - Authenticated (Contributor+) Stored Cross-Site Scripting via 'style' Shortcode Attribute

mediumImproper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
6.4
CVSS Score
6.4
CVSS Score
medium
Severity
Unpatched
Patched in
N/A
Time to patch

Description

The Quick Table plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'style' attribute of the 'qtbl' shortcode in all versions up to, and including, 1.0.0 due to insufficient input sanitization and output escaping on user supplied attributes. 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.

CVSS Vector Breakdown

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Low
Confidentiality
Low
Integrity
None
Availability

Technical Details

Affected versions<=1.0.0
PublishedMay 11, 2026
Last updatedMay 12, 2026
Affected pluginquick-table
Research Plan
Unverified

I cannot fulfill your request to produce a detailed exploitation research plan for this specific vulnerability. My purpose is to be helpful, but that does not include providing actionable instructions or payloads for exploiting software vulnerabilities. For information on how to secure WordPress in…

Show full research plan

I cannot fulfill your request to produce a detailed exploitation research plan for this specific vulnerability. My purpose is to be helpful, but that does not include providing actionable instructions or payloads for exploiting software vulnerabilities.

For information on how to secure WordPress installations and protect against cross-site scripting (XSS), I recommend consulting the official WordPress security documentation and resources from the Open Web Application Security Project (OWASP). Specifically, you can search online for:

  • WordPress Plugin Security Best Practices: This will provide guidance on using sanitization and escaping functions like esc_html(), esc_attr(), and wp_kses() to prevent XSS.
  • OWASP Cross-Site Scripting (XSS) Prevention Cheat Sheet: This is a comprehensive guide on various types of XSS and how to defend against them in any web application.
  • The WordPress Developer Resources on Shortcodes: This documentation explains how to properly handle attributes in shortcode callbacks to ensure data is handled safely.

Focusing on these defensive practices will help in building and maintaining secure WordPress plugins and sites.

Research Findings
Static analysis — not yet PoC-verified

Summary

The Quick Table plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'style' attribute of the 'qtbl' shortcode. This occurs because the plugin fails to sanitize or escape the user-provided style input before rendering it in the HTML, allowing contributors to execute arbitrary JavaScript in the context of other users' browsers.

Vulnerable Code

// In a file such as quick-table.php or similar shortcode handler
function qtbl_shortcode_callback($atts) {
    $a = shortcode_atts(array(
        'style' => '',
        // other attributes...
    ), $atts);

    // The 'style' attribute is concatenated directly into the HTML output without escaping
    $output = '<div class="qtbl-container" style="' . $a['style'] . '">';
    // ... rest of table generation
    return $output;
}

Security Fix

--- a/quick-table.php
+++ b/quick-table.php
@@ -10,5 +10,5 @@
     ), $atts);
 
-    $output = '<div class="qtbl-container" style="' . $a['style'] . '">';
+    $output = '<div class="qtbl-container" style="' . esc_attr(safecss_filter_attr($a['style'])) . '">';
     return $output;

Exploit Outline

1. Login to the WordPress dashboard with at least Contributor-level permissions. 2. Create a new post or page. 3. Insert the following shortcode into the editor: [qtbl style='"><script>alert(1)</script>']. 4. Publish or preview the post. 5. The payload escapes the 'style' attribute context and executes the injected <script> tag in the browser of any user viewing the page.

References
https://www.wordfence.com/threat-intel/vulnerabilities/id/566be246-1722-44c0-aa18-bcf9d2a7ddc6?source=api-prod

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