CVE-2026-16654: Avada (Fusion) Builder <= 3.15.6 - Authenticated (Contributor+) Stored Cross-Site Scripting via 'size' Shortcode Attribute
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 wpksespost 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.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
WordPress Avada (Fusion) Builderto a version that resolves this vulnerability.Fixed in 3.15.6 - Compensating control
Because the vulnerability is exploitable by authenticated users with contributor-level access and above, restrict contributor-level (and higher) permissions to trusted accounts only until the plugin is remediated.
Event History
Frequently Asked Questions
Which users can exploit this issue?
An attacker must be authenticated to WordPress with Contributor-level access or a higher role. No user interaction is required from the attacker once they can save the malicious shortcode content.
When does the injected script execute?
The script executes when a user accesses a page containing the injected shortcode. The impact therefore extends to users who view pages created or modified by a malicious authenticated contributor or higher-privileged user.
Why does WordPress content filtering not prevent this payload?
The payload is placed entirely inside the shortcode's size attribute and contains no HTML angle brackets. As a result, wp_kses_post does not remove it when the content is saved.
What versions are known to be affected?
Avada Fusion Builder versions up to and including 3.15.6 are affected. The provided information does not identify a fixed version.