CVE-2026-106492: Backstage: Improper preservation of access restrictions during service credential delegation

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-06 · updated 2026-10-22
Weakness: CWE-269

Description

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: before 1.49.6; from 1.50.0 before 1.54.6 — fixed in 1.49.6, 1.54.6
Linuxfoundation Backstage/Backend-Defaults: before 0.16.1; from 0.17.0 before 0.17.8 — fixed in 0.16.1, 0.17.8

How to fix

Upgrade to a fixed version: backstage 1.49.6, 1.54.6; Linuxfoundation Backstage/Backend-Defaults 0.16.1, 0.17.8. Check the vendor advisory for mitigations.

References

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