GHSA-pvv8-8fx9-h673

Path Traversal in @backstage/plugin-scaffolder-backend

### Impact A malicious actor could read sensitive files from the environment where Scaffolder tasks are run. The attack is executed by crafting a custom Scaffolder template with a `publish:github:pull-request` action using a particular source path. When the template is executed the sensitive files would be included in the published pull request. This vulnerability is mitigated by the fact that an attacker would need access to create and register templates in the Backstage catalog, and that the attack is very visible given that the exfiltration happens via a pull request. ### Patches The vulnerability is patched in the `0.15.9` release of `@backstage/plugin-scaffolder-backend`. ### For more information If you have any questions or comments about this advisory: * Open an issue in the [Backstage repository](https://github.com/backstage/backstage) * Visit our chat, linked to in [Backstage README](https://github.com/backstage/backstage)