CVE-2026-106492

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.

• https://github.com/backstage/backstage/commit/40346245c53e1bf26dee56601e95c5c4ab9cc124
• https://github.com/backstage/backstage/commit/bc80ffdafbc92ff7b8c72347eace13cb8688fd33
• https://github.com/backstage/backstage/releases/tag/v1.49.6
• https://github.com/backstage/backstage/releases/tag/v1.54.6
• https://github.com/backstage/backstage/security/advisories/GHSA-cq7v-rfgc-5c7v