What the vulnerability does
01Description
The Avada (Fusion) Builder plugin for WordPress is vulnerable to Stored Cross-Site Scripting via 'size' Shortcode Attribute in all versions up to, and including, 3.15.6 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. WordPress's wp_kses_post filter does not neutralize the payload because the injected content resides entirely within a shortcode attribute string containing no HTML angle brackets, causing kses to pass it through unchanged at save time.
Explanation of Vulnerability in Simple Terms
02Summary
Avada (Fusion) Builder versions up to 3.15.6 contain a stored cross-site scripting (XSS) vulnerability. An authenticated user with low privileges can inject malicious scripts that execute in the browsers of other site visitors, potentially compromising their sessions or stealing data. The vulnerability affects the builder interface and can impact site administrators and other users.
What an attacker can do
03Attacker Capabilities
Inject malicious scripts that run in other users' browsers when they view affected pages.
Potential impact on your site
04Site Impact
Malicious users can compromise visitor sessions, steal credentials, or deface content visible to site administrators and other users.
Conditions required to exploit
05Prerequisites
Attacker must have a low-privilege authenticated account on the site.
Key dates
06Disclosure timeline
August 28, 2026
CVE published
