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OpenAdvisories
High · 8.1 CVE-2026-106503 EUVD-2026-94068GHSA-hmp2-4m7g-22cv

Backstage: Scaffolder action input authorization bypass

Published Oct 6, 2026 · Updated Oct 9, 2026 · Assigned by GitHub_M

Description

Backstage is an open framework for building developer portals. 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. Depending on integration credentials, this could grant unauthorized access to repositories and related source-control resources. This issue is fixed in versions 3.3.1, 3.4.1, 4.0.3 and 4.1.0.

Affected products

VendorProductAffectedFixed
backstage backstage < 1.49.6, >= 1.50.0-next.0, < 1.50.5, >= 1.51.0-next.0, < 1.54.6 —
@backstage plugin-scaffolder-backend < 3.3.1, >= 3.4.0, < 3.4.1, >= 4.0.0, < 4.0.3, >= 4.0.4, < 4.1.0 —

Affected packages

EcosystemPackageAffectedFixedRecord
npm @backstage/plugin-scaffolder-backend < 3.3.1 3.3.1 GHSA-hmp2-4m7g-22cv
npm @backstage/plugin-scaffolder-backend >= 3.4.0, < 3.4.1 3.4.1 GHSA-hmp2-4m7g-22cv
npm @backstage/plugin-scaffolder-backend >= 4.0.0, < 4.0.3 4.0.3 GHSA-hmp2-4m7g-22cv
npm @backstage/plugin-scaffolder-backend >= 4.0.4, < 4.1.0 4.1.0 GHSA-hmp2-4m7g-22cv

References