CVE-2026-106503
Backstage: Scaffolder action input authorization bypass
CVSS Score
8.1
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-178 CWE-284 |
| Vendor | backstage |
| Product | backstage |
| Published | Oct 6, 2026 |
Stay Ahead of the Next One
Get instant alerts for backstage backstage
Be the first to know when new high vulnerabilities affecting backstage backstage are published — delivered to Slack, Telegram or Discord.
Get Free Alerts →
Free · No credit card · 60 sec setup
CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None
Affected Versions
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
References
github.com: https://github.com/backstage/backstage/security/advisories/GHSA-hmp2-4m7g-22cv github.com: https://github.com/backstage/backstage/commit/11c1384c0649b8ab26391c6a4e4f34b80ab0d188 github.com: https://github.com/backstage/backstage/commit/a91ed72d540e80b62a73b39bb1563ff5018d52d1 github.com: https://github.com/backstage/backstage/commit/e307e4f487103d815e484291b3fda778ab9983bf github.com: https://github.com/backstage/backstage/releases/tag/v1.49.6 github.com: https://github.com/backstage/backstage/releases/tag/v1.50.5 github.com: https://github.com/backstage/backstage/releases/tag/v1.54.6