CVE-2026-106504

Backstage is an open framework for building developer portals. Prior to 4.1.0, the @backstage/plugin-scaffolder-backend package is affected by improper input validation in scaffolder task list ordering. An authenticated Backstage user with permission to create and read relevant scaffolder tasks may be able to infer confidential task data under specific conditions. Successful exploitation requires retained task secrets, visibility of a target task, knowledge of the secret structure, and repeated requests. Fixed in version 4.1.0.

In Backstage prior to 3.3.1, 3.4.1, 4.0.3 and 4.1.0, the @backstage/plugin-scaffolder-backend package is affected by scaffolder action input authorization bypass. An authenticated user with access to affected Scaffolder templates could bypass configured action restrictions, potentially granting unauthorized access to repositories and related source-control resources.

Backstage is an open framework for building developer portals. Prior to 4.1.0, the @backstage/plugin-scaffolder-backend package could expose sensitive information in Scaffolder task failure events. Under specific template and failure conditions, an authenticated user may retrieve backend-managed credentials used during task execution from affected task events. Fixed in version 4.1.0.

In Backstage prior to 3.3.1, 3.4.1, 4.0.3 and 4.1.0, the @backstage/plugin-scaffolder-backend package is affected by improper task state validation. An authenticated user with permission to create and access Scaffolder tasks may, under specific conditions, affect files accessible to the Backstage backend, potentially compromising confidentiality, integrity, and availability.

In @backstage/plugin-scaffolder-backend prior to 4.1.0, incorrect authorization in scaffolder task listing allows an authenticated internal user to view metadata for tasks outside the intended visibility. Stored task secrets are not included, and no integrity or availability impact was identified. Fixed in version 4.1.0.

A vulnerability in the scaffolder-backend plugin of the Backstage platform allows for remote code execution by a malicious actor with access to a registered template. The issue arises from the use of a templating library that requires a sandbox, which permits code injection.