CVE-2026-106500: Backstage: Improper task state validation in Scaffolder backend

### Impact An authenticated user with permission to create and access Scaffolder tasks may, under specific timing and deployment conditions, affect files accessible to the Backstage backend. If backend application files are writable, the confidentiality, integrity, and availability of the backend may be compromised. ### Patches Patched in `@backstage/plugin-scaffolder-backend` version `4.1.0` ### Workarounds - Restrict Scaffolder task creation and task-read permissions to trusted users through the permission policy. - Limit who can register or modify templates and which Scaffolder actions may execute. - Run backend application files read-only outside a dedicated, least-privilege Scaffolder working directory. ### References - [Authorizing Scaffolder tasks, parameters, steps, and actions](https://backstage.io/docs/features/software-templates/authorizing-scaffolder-template-details/)