CVE-2026-27091: UiPress Lite Auth Bypass Vulnerability

CVE-2026-27091 Overview

CVE-2026-27091 is a Missing Authorization vulnerability (CWE-862) affecting UiPress lite, a popular WordPress plugin used for customizing the WordPress admin interface. This broken access control vulnerability allows attackers with low-level privileges to exploit incorrectly configured access control security levels, potentially gaining unauthorized access to administrative functions and sensitive data within the WordPress dashboard.

Critical Impact

Authenticated attackers with minimal privileges can bypass access control mechanisms to perform unauthorized actions, potentially compromising the integrity and confidentiality of WordPress administrative functions.

Affected Products

• UiPress lite versions up to and including 3.5.09
• WordPress installations using vulnerable UiPress lite plugin versions

Discovery Timeline

• 2026-03-19 - CVE-2026-27091 published to NVD
• 2026-03-19 - Last updated in NVD database

Technical Details for CVE-2026-27091

Vulnerability Analysis

This vulnerability falls under the category of Broken Access Control, specifically Missing Authorization (CWE-862). The UiPress lite WordPress plugin fails to properly validate user authorization before allowing access to certain functionality. When a low-privileged authenticated user makes requests to plugin endpoints, the application does not adequately verify whether the user has sufficient permissions to perform the requested action.

The network-based attack vector means exploitation can occur remotely over the internet without requiring physical access. An attacker needs only low-level authentication (such as a subscriber or contributor account) to exploit this vulnerability, with no user interaction required.

Root Cause

The root cause of this vulnerability is the absence of proper authorization checks within the UiPress lite plugin. The plugin fails to implement adequate capability checks before processing user requests, allowing authenticated users with minimal privileges to access functionality that should be restricted to administrators or higher-privileged users. This is a common pattern in WordPress plugin vulnerabilities where developers rely on authentication alone without implementing proper authorization logic.

Attack Vector

The attack vector for CVE-2026-27091 is network-based exploitation requiring low-privilege authentication. An attacker who has obtained or created a low-privileged WordPress account (such as a subscriber role) can send crafted requests to vulnerable UiPress lite endpoints. Due to the missing authorization checks, these requests are processed without verifying whether the authenticated user has the appropriate capabilities, allowing the attacker to:

1. Access administrative UiPress configurations
2. Modify plugin settings that should be restricted
3. Potentially escalate their access to sensitive WordPress dashboard functionality

The vulnerability requires authentication but does not require user interaction, making it suitable for automated exploitation once an attacker has valid credentials.

Detection Methods for CVE-2026-27091

Indicators of Compromise

• Unusual API requests to UiPress lite plugin endpoints from non-administrator user accounts
• Unexpected modifications to UiPress lite plugin settings or configurations
• Access logs showing low-privileged users accessing administrative plugin functions
• Audit trail entries indicating unauthorized changes to WordPress dashboard customizations

Detection Strategies

• Monitor WordPress access logs for requests to /wp-admin/admin-ajax.php with UiPress-related actions from non-administrator accounts
• Implement WordPress activity logging plugins to track user actions and capability usage
• Review user access patterns for anomalies, particularly subscribers or contributors accessing admin-only features
• Deploy web application firewalls (WAF) with rules to detect broken access control attempts

Monitoring Recommendations

• Enable comprehensive logging for all UiPress lite plugin actions and requests
• Set up alerts for configuration changes made by non-administrator users
• Regularly audit WordPress user accounts and their assigned roles
• Implement real-time monitoring for unauthorized access attempts to administrative endpoints

How to Mitigate CVE-2026-27091

Immediate Actions Required

• Update UiPress lite to a patched version above 3.5.09 when available from the vendor
• Review and audit all user accounts, removing unnecessary low-privileged accounts
• Temporarily deactivate UiPress lite if a patch is not immediately available
• Implement additional access control measures through security plugins or WAF rules

Patch Information

A security advisory is available from Patchstack Plugin Vulnerability Advisory. WordPress administrators should monitor the UiPress lite plugin page for security updates and apply patches as soon as they become available. It is recommended to enable automatic plugin updates for security-sensitive plugins.

Workarounds

• Restrict user registration and remove unnecessary user accounts with any level of access
• Implement IP-based access restrictions for the WordPress admin area
• Use a security plugin to enforce additional capability checks on admin AJAX actions
• Consider using a maintenance mode or temporarily disabling the plugin until a patch is released

# Configuration example: Restrict access to WordPress admin area by IP
# Add to .htaccess file in wp-admin directory
<IfModule mod_rewrite.c>
RewriteEngine on
RewriteCond %{REQUEST_URI} ^(.*)?wp-admin$
RewriteCond %{REMOTE_ADDR} !^192\.168\.1\.
RewriteCond %{REMOTE_ADDR} !^10\.0\.0\.
RewriteRule ^(.*)$ - [R=403,L]
</IfModule>