CVE-2026-106503
High
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.
SeverityHigh
CVSS8.1
Exploit probability—
Product
Linuxfoundation Backstage
PublishedOct 6, 2026
First seenOct 6, 2026
Weakness typeCWE-178CWE-178CWE-284Improper access control
How to fix
Update
- linuxfoundation backstage1.49.6, 1.50.5, 1.54.6 or later
- linuxfoundation backstage\/plugin-scaffolder-backend3.3.1, 3.4.1, 4.0.3, 4.1.0 or later
- @backstage/plugin-scaffolder-backend3.3.1, 3.4.1, 4.0.3, 4.1.0 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| linuxfoundation backstage | v < 1.49.6, 1.50.0 ≤ v < 1.50.5, 1.51.0 ≤ v < 1.54.6 | 1.49.6, 1.50.5, 1.54.6 |
| linuxfoundation backstage\/plugin-scaffolder-backend | v < 3.3.1, 3.4.0 ≤ v < 3.4.1, 4.0.0 ≤ v < 4.0.3, 4.0.4 ≤ v < 4.1.0 | 3.3.1, 3.4.1, 4.0.3, 4.1.0 |
| @backstage/plugin-scaffolder-backendnpm | v < 3.3.1, 3.4.0 ≤ v < 3.4.1, 4.0.0 ≤ v < 4.0.3, 4.0.4 ≤ v < 4.1.0 | 3.3.1, 3.4.1, 4.0.3, 4.1.0 |
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