Backstage: Scaffolder action input authorization bypass

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-106503
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-06 22:17:05 UTC
Updated2026-10-13 14:37:56 UTC
DescriptionBackstage 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.

Risk And Classification

Primary CVSS: v3.1 8.1 HIGH from [email protected]

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

EPSS: 0.003570000 probability, percentile 0.274850000 (date 2026-10-11)

Problem Types: CWE-178 | CWE-284 | CWE-178 CWE-178: Improper Handling of Case Sensitivity | CWE-284 CWE-284: Improper Access Control

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary8.1HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
3.1CNADECLARED8.1HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Linuxfoundation Backstage/plugin-scaffolder-backend All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Backstage Backstage affected < 1.49.6 Not specified
CNA Backstage Backstage affected >= 1.50.0-next.0, < 1.50.5 Not specified
CNA Backstage Backstage affected >= 1.51.0-next.0, < 1.54.6 Not specified
CNA @backstage Plugin-scaffolder-backend affected < 3.3.1 Not specified
CNA @backstage Plugin-scaffolder-backend affected >= 3.4.0, < 3.4.1 Not specified
CNA @backstage Plugin-scaffolder-backend affected >= 4.0.0, < 4.0.3 Not specified
CNA @backstage Plugin-scaffolder-backend affected >= 4.0.4, < 4.1.0 Not specified

References

ReferenceSourceLinkTags
github.com/backstage/backstage/commit/e307e4f487103d815e484291b3fda778ab... [email protected] github.com Patch
github.com/backstage/backstage/releases/tag/v1.50.5 [email protected] github.com Patch, Release Notes
github.com/backstage/backstage/releases/tag/v1.49.6 [email protected] github.com Patch, Release Notes
github.com/backstage/backstage/security/advisories/GHSA-hmp2-4m7g-22cv [email protected] github.com Mitigation, Vendor Advisory
github.com/backstage/backstage/commit/11c1384c0649b8ab26391c6a4e4f34b80a... [email protected] github.com Patch
github.com/backstage/backstage/releases/tag/v1.54.6 [email protected] github.com Patch, Release Notes
github.com/backstage/backstage/commit/a91ed72d540e80b62a73b39bb1563ff501... [email protected] github.com Patch
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