Plugin scaffolder backend: Backstage: Scaffolder action input authorization bypass (CVE-2026-106503)
Description
An authorization bypass vulnerability exists in the Backstage plugin-scaffolder-backend that allows an authenticated user with access to certain Scaffolder templates to bypass configured action restrictions. This could lead to unauthorized access to repositories and source-control resources depending on integration credentials. The issue is patched in version 4.1.0 of the plugin. Workarounds include restricting affected actions to trusted users and using least-privilege credentials for source-control integrations.
CVSS v3.1
Score 8.1high
Affected software
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-106503 is an authorization bypass vulnerability in the @backstage/plugin-scaffolder-backend component of Backstage. Authenticated users with access to vulnerable Scaffolder templates can circumvent action restrictions, potentially gaining unauthorized access to repositories and related source-control resources depending on the privileges of the integration credentials. The vulnerability affects multiple versions prior to 4.1.0 and is addressed by an official patch in version 4.1.0.
Potential Impact
An attacker with authenticated access to affected Scaffolder templates can bypass action restrictions, potentially leading to unauthorized access to source-control repositories and resources. The impact includes confidentiality and integrity compromise of source code repositories, but does not affect availability. The CVSS score is 8.1 (High), reflecting the significant confidentiality and integrity impact with network attack vector and low attack complexity.
Mitigation Recommendations
An official patch is available in @backstage/plugin-scaffolder-backend version 4.1.0. Users should upgrade to this version to remediate the vulnerability. As a workaround, restrict affected Scaffolder actions to trusted users only and configure source-control integrations with least-privilege credentials to limit potential unauthorized access.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-hmp2-4m7g-22cv
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-106503"]
- Ecosystems
- ["npm"]
- Database Specific Severity
- HIGH
- Cvss Version
- 3.1
Threat ID: 6ac6c0012cdf04f6568291be
Added to database: 10/07/2026, 21:56:17 UTC
Last enriched: 10/07/2026, 22:15:38 UTC
Last updated: 10/07/2026, 22:15:38 UTC
Views: 3
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