CVE-2026-106503

Backstage: Scaffolder action input authorization bypass

HIGH
8.1
CVSS Score
Published: October 6, 2026 at 09:37 PM UTC
Updated: October 13, 2026 at 02:37 PM UTC
4 products affected across 2 vendorsBackstageBackstage /plugin Scaffolder BackendBackstage

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Severity
HIGH8.1
Exploit prediction
EPSS 0.5%
SSVC
No known exploit

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

References (7)

SSVC — Action Prioritization

SSVCNo known exploitNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.1HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-178CWE-284

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