CVE-2026-1509: Avada Builder Privilege Escalation Flaw

CVE-2026-1509 Overview

The Avada (Fusion) Builder plugin for WordPress contains an Arbitrary WordPress Action Execution vulnerability affecting all versions up to and including 3.15.1. This security flaw stems from the plugin's output_action_hook() function, which improperly accepts user-controlled input to trigger any registered WordPress action hook without adequate authorization checks. Authenticated attackers with Subscriber-level access or higher can exploit this vulnerability via the Dynamic Data feature to execute arbitrary WordPress action hooks, potentially leading to privilege escalation, file inclusion, denial of service, or other security impacts depending on available action hooks in the WordPress installation.

Critical Impact

Authenticated attackers with low-privilege Subscriber accounts can execute arbitrary WordPress action hooks, potentially escalating privileges or compromising site integrity depending on registered hooks.

Affected Products

• Avada (Fusion) Builder Plugin for WordPress versions ≤ 3.15.1
• WordPress installations using vulnerable Avada Builder versions
• Sites with registered action hooks that perform sensitive operations

Discovery Timeline

• April 15, 2026 - CVE-2026-1509 published to NVD
• April 15, 2026 - Last updated in NVD database

Technical Details for CVE-2026-1509

Vulnerability Analysis

This vulnerability is classified under CWE-94 (Improper Control of Generation of Code - Code Injection). The core issue lies in the output_action_hook() function within the Avada (Fusion) Builder plugin, which processes user-supplied input to dynamically invoke WordPress action hooks. The function fails to validate whether the authenticated user has appropriate permissions to trigger the requested action hook, creating an authorization bypass condition.

The vulnerability is particularly dangerous in WordPress environments because action hooks serve as the framework's event system. Many plugins and themes register custom action hooks that perform privileged operations such as user role modifications, file system operations, database queries, or configuration changes. By allowing low-privilege users to invoke these hooks arbitrarily, attackers can chain exploits to achieve effects far beyond their intended access level.

Root Cause

The root cause is a missing authorization check in the output_action_hook() function. The function accepts hook names from user-controlled input via the Dynamic Data feature without verifying:

1. Whether the requesting user has capability to execute the specified action
2. Whether the action hook is intended to be publicly accessible
3. Whether additional security nonces or tokens are required for sensitive hooks

This design flaw violates the principle of least privilege and allows authenticated users to bypass intended access controls.

Attack Vector

The attack is network-accessible and requires low-privilege authentication (Subscriber-level account). An attacker can exploit this vulnerability through the following mechanism:

The attacker first authenticates to the WordPress site with a Subscriber-level account, which is typically the lowest privilege level available to registered users. They then interact with the Avada Builder's Dynamic Data feature, crafting a malicious request that specifies a target action hook name. When the plugin processes this request, the output_action_hook() function executes the specified hook without checking whether the Subscriber should have access to trigger that particular action.

The actual impact depends on which action hooks are registered in the WordPress installation. For example, if a hook exists that modifies user roles or installs plugins, the attacker could leverage this to escalate to Administrator privileges. Other scenarios include triggering hooks that include files, modify database entries, or cause resource exhaustion.

For detailed technical analysis, refer to the Wordfence Vulnerability Report.

Detection Methods for CVE-2026-1509

Indicators of Compromise

• Unusual action hook executions originating from low-privilege user sessions
• Subscriber-level users triggering administrative WordPress actions
• Unexpected modifications to user roles, plugins, or site configurations
• Log entries showing Dynamic Data feature requests with unusual hook names

Detection Strategies

• Monitor WordPress debug logs for unexpected do_action() calls triggered by non-admin users
• Implement Web Application Firewall (WAF) rules to detect anomalous requests to Dynamic Data endpoints
• Review user activity logs for Subscriber accounts performing actions beyond their scope
• Deploy WordPress security plugins that track hook execution patterns

Monitoring Recommendations

• Enable detailed logging for all authenticated user activities in WordPress
• Configure alerts for privilege escalation events or unauthorized role changes
• Monitor file system integrity for unexpected modifications
• Track plugin and theme installation or modification events from non-admin sessions

How to Mitigate CVE-2026-1509

Immediate Actions Required

• Update Avada (Fusion) Builder plugin to the latest patched version immediately
• Audit user accounts and remove unnecessary Subscriber-level access
• Review registered action hooks for sensitive operations that could be abused
• Temporarily disable the Dynamic Data feature if updates cannot be applied immediately

Patch Information

ThemeFusion has released security updates addressing this vulnerability. Administrators should update the Avada (Fusion) Builder plugin to a version newer than 3.15.1. The patch adds proper authorization checks to the output_action_hook() function to ensure users can only trigger hooks appropriate to their capability level.

For update instructions and changelog details, refer to the Avada Documentation Change Log.

Workarounds

• Restrict registration and Subscriber-level account creation until the patch is applied
• Implement additional authorization checks via a custom plugin that filters hook execution
• Use a WordPress security plugin with virtual patching capabilities to block exploit attempts
• Consider temporarily deactivating the Avada Builder plugin in high-risk environments

# Configuration example - Restrict subscriber capabilities via wp-config.php
# Add to your theme's functions.php to prevent subscribers from accessing Dynamic Data
add_action('init', function() {
    if (current_user_can('subscriber') && !current_user_can('edit_posts')) {
        // Remove capabilities that could be abused
        remove_action('wp_ajax_fusion_builder_dynamic_data', 'fusion_builder_dynamic_data_callback');
    }
});