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CVE-2026-106498

Backstage: Improper URL validation in catalog entity placeholder resolution

Impact

Backstage is an open framework for building developer portals. Prior to 3.5.1, 3.6.2, 3.7.2, 3.8.2 and 3.9.1, the @backstage/plugin-catalog-backend package is affected by improper url validation in catalog entity placeholder resolution. An authenticated Backstage user could craft a catalog entity with placeholder directives that reference resources outside the entity's source repository. Under certain configurations, this could allow access to data not intended to be available to the user. This issue is fixed in versions 3.5.1, 3.6.2, 3.7.2, 3.8.2 and 3.9.1.

Affected packages

EcosystemPackageAffectedFixed in
npm@backstage/plugin-catalog-backend< 3.9.13.9.1

Affected products

VendorProductAffected versions
LinuxfoundationBackstage Plugin-Catalog-Backend
before 3.5.1
from 3.6.0 before 3.6.2
from 3.7.0 before 3.7.2
from 3.8.0 before 3.8.2
from 3.9.0 before 3.9.1
LinuxfoundationBackstage
before 1.49.6
from 1.50.0 before 1.50.5
from 1.51.0 before 1.51.3
from 1.52.0 before 1.53.2
from 1.54.0 before 1.54.6

Weakness classification

CWE-863CWE-918

References