CVE-2026-16654

Avada (Fusion) Builder <= 3.15.6 - Authenticated (Contributor+) Stored Cross-Site Scripting via 'size' Shortcode Attribute

2026-08-27 15:41
João Pedro Soares de Alcântara

Strategic Overview

Status
Patched in 3.16
Affected Plugin
Avada (Fusion) Builder
Affected Version
<= 3.15.6
CVSS
6.4Medium
Weakness type
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVE
CVE-2026-16654
View all Avada (Fusion) Builder vulnerabilities

At a glance

CVE-2026-16654 is a medium-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the Avada (Fusion) Builder WordPress plugin, affecting versions <= 3.15.6. It carries a CVSS score of 6.4 (reachable over the network; low attack complexity). Exploitation requires an authenticated account at Contributor level or above. The issue is fixed in version 3.16; sites on affected versions should update now. Disclosed August 2026, reported by João Pedro Soares de Alcântara.

Vulnerability Overview

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.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no interaction from a victim user.

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Avada (Fusion) Builder <= 3.15.6 carries this weakness at size, and reaching it takes an account at Contributor level or above. Cross-site scripting happens when input from a request is written into a page without being escaped for the context it lands in, so the browser parses attacker-supplied text as markup or script.

Injected script runs with the privileges of whoever views the affected page, which is how these flaws turn into administrator session theft, silent account creation or persistent backdoors in page content. For Avada (Fusion) Builder the fix is 3.16: builds <= 3.15.6 are affected, anything from 3.16 onward is not.

Remediation

Update to version 3.16, or a newer patched version

How does WordSec protect against this?

An attacker needs Contributor access first, so the firewall sees the attempt as traffic from a logged-in account: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Avada (Fusion) Builder 3.16 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2026-16654https://www.wordfence.com/threat-intel/vulnerabilities/id/8d3c29b8-7910-41f1-b203-6c89519f8806https://nvd.nist.gov/vuln/detail/CVE-2026-16654

Related records

Vulnerability data © Defiant, Inc., provided under the Wordfence Intelligence T&C