CVE-2026-12256: Themefusion Fusion Builder

High severity, CVSS 8.8. EPSS: 0.5% chance of exploitation in the next 30 days.

Deserialization of Untrusted Data vulnerability in ThemeFusion Fusion Builder fusion-builder allows Object Injection.This issue affects Fusion Builder: from n/a through 3.15.3.

Affected products

• Themefusion Fusion Builder: up to and including 3.15.3

Published 2026-06-17. Last modified 2026-10-01.