CVE-2026-106492: @backstage Backend-Defaults

High severity, CVSS 7.6. EPSS: 0.2% chance of exploitation in the next 30 days.

Backstage is an open framework for building developer portals. Prior to 0.16.1 and 0.17.8, the @backstage/backend-defaults package is affected by improper preservation of access restrictions during service credential delegation. An external service credential configured with access restrictions (e.g., read-only) could bypass those restrictions by routing requests through plugin delegation paths. This could allow a restricted service to perform operations beyond its intended scope, including write operations on plugins it was restricted to read-only access for. This issue is fixed in versions 0.16.1 and 0.17.8.

Affected products

• @backstage Backend-Defaults: before 0.16.1 (fixed in 0.16.1); from 0.17.0, before 0.17.8 (fixed in 0.17.8)
• Backstage Backstage: before 1.49.6 (fixed in 1.49.6); from 1.50.0-next.0, before 1.54.6 (fixed in 1.54.6)

Published 2026-10-06. Last modified 2026-10-09.