CVE-2026-6279
CriticalCVSS 9.8Exploitation Probability (EPSS)
High risk80th percentile - higher than 80% of all known CVEs
Summary
The Avada Builder (fusion-builder) plugin for WordPress up to version 3.15.2 is vulnerable to unauthenticated remote code execution via PHP function injection. The vulnerability allows attacker-controlled values from a base64-decoded JSON blob to be passed directly to call_user_func() without validation. Exploitation is possible through the fusion_get_widget_markup AJAX endpoint, which is accessible to unauthenticated users, and the nonce is deterministically exposed on public pages.
Risk Assessment
An unauthenticated attacker can execute arbitrary PHP code on the site, potentially leading to full compromise of the WordPress site, data theft, and further attacks.
Recommendation
Update the Avada Builder plugin to version 3.15.3 or later immediately.
Original NVD description (English source)
The Avada Builder (fusion-builder) plugin for WordPress is vulnerable to Unauthenticated Remote Code Execution via PHP Function Injection in versions up to and including 3.15.2. This is due to the `wp_conditional_tags` case in `Fusion_Builder_Conditional_Render_Helper::get_value()` passing attacker-controlled values from a base64-decoded JSON blob directly to `call_user_func()` without any allowlist validation. This is exploitable by unauthenticated attackers through the `fusion_get_widget_markup` AJAX endpoint, which is registered for non-privileged (unauthenticated) users via `wp_ajax_nopriv_fusion_get_widget_markup`. The endpoint is protected only by a nonce (`fusion_load_nonce`), but this nonce is generated for user ID 0 and is deterministically exposed in the JavaScript output of any public-facing page containing a Post Cards (`[fusion_post_cards]`) or Table of Contents (`[fusion_table_of_contents]`) element. This makes it possible for unauthenticated attackers to execute arbitrary code on affected sites.