CVE-2026-106489: @backstage Plugin-Techdocs-Backend

Medium severity, CVSS 6.5. EPSS: 0.3% chance of exploitation in the next 30 days.

Backstage is an open framework for building developer portals. Prior to 2.2.4, the @backstage/plugin-techdocs-backend package is affected by improper authorization enforcement for techdocs static content. An authenticated user with access to one TechDocs documentation site could craft a URL able to read documentation belonging to a different entity. This only affects deployments using the external TechDocs builder with an external storage provider (S3, GCS, etc.) and the permission framework enabled. Instances that do not use the permission framework are unaffected, since TechDocs content is visible to all authenticated users by design. This issue is fixed in version 2.2.4.

Affected products

• @backstage Plugin-Techdocs-Backend: before 2.2.4 (fixed in 2.2.4)
• Backstage Backstage: before 1.54.6 (fixed in 1.54.6)

Published 2026-10-06. Last modified 2026-10-07.