CVE-2026-106500

HIGH 8.5

Backstage: Improper task state validation in Scaffolder backend

CVSS Score

8.5

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 improper task state validation in scaffolder backend. An authenticated user with permission to create and access Scaffolder tasks may, under specific timing and deployment conditions, affect files accessible to the Backstage backend. If backend application files are writable, the confidentiality, integrity, and availability of the backend may be compromised. This issue is fixed in versions 3.3.1, 3.4.1, 4.0.3 and 4.1.0.

CWE	CWE-59 CWE-362
Vendor	backstage
Product	backstage
Published	Oct 6, 2026

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CVSS v3 Breakdown

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

Attack Vector

Network

Attack Complexity

High

Privileges Required

Low

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

High

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

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/backstage/backstage/security/advisories/GHSA-xvgh-hmx8-9xxf github.com: https://github.com/backstage/backstage/commit/0d24f1b8701f3dde6cd597f81997c1ea873a43ae github.com: https://github.com/backstage/backstage/commit/56be299dd3ef6706e13e76ea2f8a9b0dd0b6413d github.com: https://github.com/backstage/backstage/commit/9e86c95a1a3ddfd54db03731cd8678aa63495175 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