CVE-2026-106500

High

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 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.

SeverityHigh
CVSS8.5
Exploit probability—
ProductLinuxfoundation Backstage
PublishedOct 6, 2026
First seenOct 6, 2026

How to fix

Update
  • linuxfoundation backstage1.49.6, 1.50.5, 1.54.6 or later
  • linuxfoundation backstage\/plugin-scaffolder-backend3.3.1, 3.4.1, 4.0.3, 4.1.0 or later
  • @backstage/plugin-scaffolder-backend4.1.0 or later

Affected products

ProductAffected versionsFixed in
linuxfoundation backstagev < 1.49.6, 1.50.0 ≤ v < 1.50.5, 1.51.0 ≤ v < 1.54.61.49.6, 1.50.5, 1.54.6
linuxfoundation backstage\/plugin-scaffolder-backendv < 3.3.1, 3.4.0 ≤ v < 3.4.1, 4.0.0 ≤ v < 4.0.3, 4.0.4 ≤ v < 4.1.03.3.1, 3.4.1, 4.0.3, 4.1.0
@backstage/plugin-scaffolder-backendnpmv < 4.1.04.1.0

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