The templating library used by the scaffolder backend assumes that templates are trusted which is an undesired property of the scaffolder-backend. This has now been mitigated by sandboxing the template code execution. A malicious actor with write access to a registered scaffolder template could manipulate the template in a way that allows for remote code execution on the scaffolder-backend instance. This was only exploitable in the template yaml definition itself and not by user input data. Fixed in backstage 0.15.14.