Backstage is an open framework for building developer portals. Prior to 3.9.1, the @backstage/plugin-catalog-backend package is affected by inconsistent catalog property permission evaluation. In deployments that use affected value-based catalog permission conditions as a confidentiality boundary, an authenticated user could receive catalog entity data that policy authors intended to restrict. This issue is fixed in version 3.9.1.
https://github.com/backstage/backstage/security/advisories/GHSA-8429-xpcj-3cg5
https://github.com/backstage/backstage/releases/tag/v1.54.6
https://github.com/backstage/backstage/commit/21424faa2e280a6bc6b9e5c5245952f16aafca7b