CVE-2026-106500 PUBLISHED

Backstage: Improper task state validation in Scaffolder backend

Assigner: GitHub_M
Reserved: 06.10.2026 Published: 06.10.2026 Updated: 07.10.2026

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.

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
CVSS Score: 8.5

Product Status

Vendor backstage
Product backstage
Versions
  • Version < 1.49.6 is affected
  • Version >= 1.50.0-next.0, < 1.50.5 is affected
  • Version >= 1.51.0-next.0, < 1.54.6 is affected
Vendor @backstage
Product plugin-scaffolder-backend
Versions
  • Version < 3.3.1 is affected
  • Version >= 3.4.0, < 3.4.1 is affected
  • Version >= 4.0.0, < 4.0.3 is affected
  • Version >= 4.0.4, < 4.1.0 is affected

References

Problem Types

  • CWE-59: Improper Link Resolution Before File Access ('Link Following') CWE
  • CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') CWE