Backstage: Improper preservation of access restrictions during service credential delegation

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.6 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:L

EPSS

• CVE-2026-106492: 0.21% estimated exploitation activity in the next 30 days; percentile 10.94 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact 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. Patches Patched in @backstage/backend-defaults version 0.17.8 Workarounds If you're unable to upgrade immediately: - If practical, replace restricted credentials with separate, purpose-specific unrestricted credentials scoped to trusted consumers. - Restrict network-level access to Backstage backend API endpoints to trusted callers only.

Published by the source

7 Oct 2026, 17:59 UTC

Last modified by the source

7 Oct 2026, 18:15 UTC

Source last checked

26 Oct 2026, 13:07 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-cq7v-rfgc-5c7v

2. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GHSA-cq7v-rfgc-5c7v

3. Revision 1 · created · 23 Oct 2026

   Published from ghsa record GHSA-cq7v-rfgc-5c7v

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# Patch Next advisory brief: CVE-2026-106492

Advisory: Backstage: Improper preservation of access restrictions during service credential delegation
IDs: CVE-2026-106492, GHSA-cq7v-rfgc-5c7v
Record: https://patchnext.com/advisories/cve-2026-106492 (revision 3, source checked 26 Oct 2026, 13:07 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.6)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: @backstage/backend-defaults 0.17.8. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm @backstage/backend-defaults: affected < 0.17.8; fixed in 0.17.8

## Suggested inspection (read-only)
- `npm ls @backstage/backend-defaults --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on @backstage/backend-defaults.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-cq7v-rfgc-5c7v (GitHub-reviewed advisory GHSA-cq7v-rfgc-5c7v lists affected ranges: npm @backstage/backend-defaults >=0 <0.17.8)
- Verified: https://osv.dev/vulnerability/GHSA-cq7v-rfgc-5c7v (OSV record GHSA-cq7v-rfgc-5c7v lists affected ranges: npm @backstage/backend-defaults >=0 <0.17.8 (fixed))

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