CVE-2025-52804: uxper Nuss Authorization Bypass Vulnerability

CVE-2025-52804 Overview

CVE-2025-52804 is a Missing Authorization vulnerability (CWE-862) affecting the Nuss WordPress theme developed by uxper. This broken access control flaw allows attackers to access functionality that is not properly constrained by Access Control Lists (ACLs), potentially enabling unauthorized actions within WordPress sites using the vulnerable theme.

Critical Impact

Attackers can bypass access control mechanisms to reach protected functionality, potentially leading to unauthorized data access, configuration changes, or privilege escalation within affected WordPress installations.

Affected Products

• Nuss WordPress Theme versions through 1.3.7.1
• WordPress installations using the Nuss theme
• Websites with the uxper Nuss theme enabled

Discovery Timeline

• 2025-07-16 - CVE-2025-52804 published to NVD
• 2026-04-15 - Last updated in NVD database

Technical Details for CVE-2025-52804

Vulnerability Analysis

This vulnerability stems from missing authorization checks within the Nuss WordPress theme. The flaw is classified under CWE-862 (Missing Authorization), indicating that the application fails to perform proper access control validation before granting access to protected resources or functionality.

In a properly secured WordPress theme, access to sensitive functions should be gated by capability checks using WordPress's built-in permission system (such as current_user_can()). When these checks are absent, any user—including unauthenticated visitors—may be able to invoke functionality that should be restricted to administrators or other privileged roles.

The vulnerability affects Nuss theme versions from the initial release through version 1.3.7.1. According to the Patchstack advisory, this represents a broken access control condition that can be exploited remotely.

Root Cause

The root cause of CVE-2025-52804 is the absence of proper authorization checks in one or more theme functions. WordPress themes and plugins should validate user permissions before executing sensitive operations. When these validation routines are missing or improperly implemented, attackers can directly invoke protected functionality by crafting requests to vulnerable endpoints.

Common manifestations of this vulnerability type in WordPress themes include:

• AJAX handlers without check_ajax_referer() or capability checks
• Admin-only functions accessible via direct URL requests
• REST API endpoints missing proper permission callbacks
• Theme customizer options accessible without authentication

Attack Vector

Exploitation of this vulnerability requires network access to the target WordPress installation. An attacker can potentially bypass intended access restrictions by directly requesting vulnerable theme endpoints or functions. The attack does not require prior authentication, making it exploitable by anonymous remote attackers.

The vulnerability allows accessing functionality not properly constrained by ACLs, which means an attacker could potentially:

• Access or modify theme settings
• Retrieve sensitive configuration data
• Trigger administrative functions
• Potentially escalate privileges within the WordPress environment

Detection Methods for CVE-2025-52804

Indicators of Compromise

• Unusual AJAX requests to theme-specific endpoints from unauthenticated sessions
• Unexpected theme setting modifications without corresponding admin activity
• Access logs showing requests to Nuss theme files from suspicious IP addresses
• Database changes to theme-related options without administrator actions

Detection Strategies

• Monitor WordPress access logs for requests to /wp-content/themes/nuss/ endpoints from unauthenticated users
• Implement Web Application Firewall (WAF) rules to detect broken access control attempts
• Review WordPress audit logs for unauthorized theme configuration changes
• Use security plugins to scan for vulnerable theme versions

Monitoring Recommendations

• Enable WordPress debug logging to capture unauthorized access attempts
• Configure alerts for theme option modifications outside of admin sessions
• Regularly audit installed theme versions against known vulnerability databases
• Implement real-time monitoring of WordPress AJAX handlers and REST API endpoints

How to Mitigate CVE-2025-52804

Immediate Actions Required

• Identify if your WordPress installation uses the Nuss theme by uxper
• Check the current theme version in Appearance > Themes in the WordPress admin panel
• Update the Nuss theme to a patched version if available from the vendor
• Consider temporarily switching to an alternative theme if no patch is available

Patch Information

Website administrators should check for updates to the Nuss theme through the WordPress admin dashboard or the theme vendor's official channels. Review the Patchstack vulnerability database entry for the latest remediation guidance and patch availability.

If a patched version is not yet available, consider implementing the workarounds below while monitoring for an official security update from uxper.

Workarounds

• Restrict access to WordPress admin and AJAX endpoints at the web server level
• Implement additional authentication layers using security plugins
• Use a Web Application Firewall (WAF) to filter malicious requests targeting the theme
• Temporarily deactivate the Nuss theme and switch to a secure alternative until patched

# Example: Restrict direct access to theme files via .htaccess
# Add to /wp-content/themes/nuss/.htaccess

<FilesMatch "\.(php)$">
    Order Deny,Allow
    Deny from all
    Allow from 127.0.0.1
</FilesMatch>