CVE-2026-106492: Backstage Improper Preservation Of Access Restrictions Vulnerability

HIGH
Advisory Identifier: GHSA-cq7v-rfgc-5c7v
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CVSS 7.6
CWE-269 CWE-863
Published
Advisory Summary

CVE-2026-106492 is a HIGH (CVSS 7.6) improper preservation of access restrictions vulnerability (CWE-269: Improper Privilege Management) affecting Backstage libraries in the npm ecosystem. The issue involves improper preservation of access restrictions during service credential delegation. Remediation is available by upgrading affected packages to version 0.17.8.

CVE-2026-106492 at a Glance

CVE Identifier CVE-2026-106492
GHSA Identifier GHSA-cq7v-rfgc-5c7v
Severity HIGH
CVSS v3.1 Base Score 7.6
CWE Classification CWE-269: Improper Privilege Management
Affected Product Backstage
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 7.6

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:L).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality Low (C:L)
Integrity High (I:H)
Availability Low (A:L)

How to Fix CVE-2026-106492

To remediate this vulnerability, upgrade all affected Backstage dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

@backstage/backend-defaults fixed: 0.17.8 
npm install @backstage/backend-defaults@0.17.8
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls @backstage/backend-defaults

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-106492, inspect your project dependencies using npm:

npm ls @backstage/backend-defaults

Analyze the terminal output to locate any version of Backstage in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.17.8), your application is affected.

Note: The npm ls @backstage/backend-defaults command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-269: Improper Privilege Management, where the product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor. In Backstage, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### 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.

CVE-2026-106492 Affected Backstage Versions

1 component(s)
Fixed Versions:
0.17.8
Product / Package Ecosystem Affected Versions Fixed Version
@backstage/backend-defaults
npm/@backstage/backend-defaults
npm
< 0.17.8
0.17.8

References

GitHub Advisory / Wiki ADVISORY
https://github.com/backstage/backstage/security/advisories/GHSA-cq7v-rfgc-5c7v
NVD — CVE-2026-106492 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-106492
Security Fix Commit FIX COMMIT
https://github.com/backstage/backstage/commit/40346245c53e1bf26dee56601e95c5c4ab9cc124
Security Fix Commit FIX COMMIT
https://github.com/backstage/backstage/commit/bc80ffdafbc92ff7b8c72347eace13cb8688fd33
Backstage Source Repository REPOSITORY
https://github.com/backstage/backstage
Backstage Release RELEASE
https://github.com/backstage/backstage/releases/tag/v1.49.6
Backstage Release RELEASE
https://github.com/backstage/backstage/releases/tag/v1.54.6

Frequently Asked Questions

What is CVE-2026-106492?
CVE-2026-106492 is a security vulnerability in Backstage involving Improper preservation of access restrictions during service credential delegation under CWE-269: Improper Privilege Management.
Which Backstage versions are affected?
Affected versions include releases prior to 0.17.8 across affected packages: @backstage/backend-defaults.
What version fixes CVE-2026-106492?
Upgrading to 0.17.8 (or the latest patched release for your respective branch) resolves the vulnerability.
Is @backstage/backend-defaults affected?
Yes, @backstage/backend-defaults is affected in releases prior to 0.17.8. Upgrade your dependency to 0.17.8 or later.
What is the CVSS score of CVE-2026-106492?
CVE-2026-106492 has a CVSS v3.1 base score of 7.6 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:L.
What CWE is associated with CVE-2026-106492?
CVE-2026-106492 is classified under CWE-269: Improper Privilege Management (The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor.).
How can I check npm dependencies for CVE-2026-106492?
Run the dependency tree command: 'npm ls @backstage/backend-defaults'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-cq7v-rfgc-5c7v",
  "modified" : "2026-10-07T17:59:44Z",
  "published" : "2026-10-07T17:59:43Z",
  "aliases" : [ "CVE-2026-106492" ],
  "summary" : "Backstage: Improper preservation of access restrictions during service credential delegation",
  "details" : "### Impact\n\nAn 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.\n\n### Patches\n\nPatched in `@backstage/backend-defaults` version `0.17.8`\n\n### Workarounds\n\nIf you're unable to upgrade immediately:\n\n- If practical, replace restricted credentials with separate, purpose-specific unrestricted credentials scoped to trusted consumers.\n- Restrict network-level access to Backstage backend API endpoints to trusted callers only.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:L"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@backstage/backend-defaults"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.17.8"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/backstage/backstage/security/advisories/GHSA-cq7v-rfgc-5c7v"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-106492"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/backstage/backstage/commit/40346245c53e1bf26dee56601e95c5c4ab9cc124"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/backstage/backstage/commit/bc80ffdafbc92ff7b8c72347eace13cb8688fd33"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/backstage/backstage"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/backstage/backstage/releases/tag/v1.49.6"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/backstage/backstage/releases/tag/v1.54.6"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-269", "CWE-863" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-10-07T17:59:43Z",
    "nvd_published_at" : "2026-10-06T21:17:18Z"
  }
}