CVE-2026-91145 [HIGH] – Activiti through 7.1.0.M6 fails to validate hash-brace deferred expressions in process var

Activiti through 7.1.0.M6 fails to validate hash-brace deferred expressions in process variables, allowing attackers to bypass expression filtering. Attackers can inject expressions beginning with #{ that are stored and later evaluated in the full Spring context when a mail task uses variable-backed body fields, enabling method invocation on application beans.