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Findings

CVE-2026-106495

Backstage: Improper access control in backend action invocation

Published Oct 12, 2026 · corrected/updated Oct 15, 2026 · backstage backstage · evidence confidence high

Backstage is an open framework for building developer portals. Prior to 0.17.8, the @backstage/backend-defaults package is affected by improper access control in backend action invocation. An authenticated user could invoke actions that an operator had excluded through action configuration. Existing action permissions and downstream authorization remain enforced. This issue is fixed in version 0.17.8.

Grounded briefings

Catalog interpretations for three audiences. Each brief cites ingested metadata and the original advisories below. They are not independent research and they do not invent exploit steps.

Executive

CVE-2026-106495 is a medium public vulnerability record for backstage backstage. It is not currently listed in the CISA Known Exploited catalog. Check the linked vendor or CERT advisories for patch status. This summary is a catalog interpretation of the ingested metadata and cites the original advisories below.

System administrator

Identify whether backstage backstage is in your estate, then compare installed versions with the affected ranges. Affected packages or ranges on record: @backstage; @backstage/backend-defaults (0 → 0.17.8); @backstage/backend-defaults (< 0.17.8); @backstage backend-defaults. Check the linked vendor or CERT advisories for patch status. Prefer the vendor or distribution advisory linked in Sources before changing production systems. This is a catalog interpretation, not a runbook.

Security analyst

Signals on file: CVSS 4.3, EPSS 0.2%. It is not currently listed in the CISA Known Exploited catalog. Weakness classes: CWE-284. Sources contributing to this record: cve_org, epss, github, gitlab. Public exploit references, when present, are outbound links only and are not proof of active exploitation. This is a catalog interpretation of stored metadata.

Exploitation and remediation

  • Exploitation evidence

    Not listed as known exploited in CISA KEV. Not in the CISA KEV catalog.

  • Patch and remediation

    No required-action text is stored yet. Use the vendor or CERT links in Sources for patch availability.

  • Safe detection guidance

    Compare installed versions with the affected ranges below and verify the advisory from the original publisher. This site stores metadata and outbound links only; it does not ship exploit code or proof-of-concept payloads.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 15, 2026 · GitHub Advisory Database

    Detected

    ### Impact An authenticated user could invoke actions that an operator had excluded through action configuration. Existing action permissions and downstream authorization remain enforced. ### Patches Patched in version ### Workarounds Limit access to action invocation endpoints to trusted service callers until upgrading.

  2. Oct 15, 2026 · GitHub Advisory Database

    Fix available

    @backstage/backend-defaults fixed in 0.17.8

  3. Oct 15, 2026 · GitHub Advisory Database

    Fix available

    @backstage/backend-defaults fixed in 0.17.8

  4. Oct 15, 2026 · GitHub Advisory Database

    Updated

    ### Impact An authenticated user could invoke actions that an operator had excluded through action configuration. Existing action permissions and downstream authorization remain enforced. ### Patches Patched in version ### Workarounds Limit access to action invocation endpoints to trusted service callers until upgrading.

Affected

  • npm @backstageversion unspecified
  • npm @backstage/backend-defaults0 → 0.17.8
  • npm @backstage/backend-defaults< 0.17.8
  • vendor @backstage backend-defaultsversion unspecified
  • vendor backstage backstageversion unspecified

Sources

  • CVE.orgVulnerability recordCVE-2026-106495

    Backstage is an open framework for building developer portals. Prior to 0.17.8, the @backstage/backend-defaults package is affected by improper access control in backend action invocation. An authenticated user could invoke actions that an operator had excluded through action con

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-106495

    30-day exploitation probability 0.2%

    first.org
  • GitHub Advisory DatabasePackage advisoryGHSA-3xr5-8w6c-p5gw

    GitHub Advisory Database record mirrored by OSV.

    github.com
  • GitLab Advisory DatabasePackage advisoryCVE-2026-106495

    An authenticated user could invoke actions that an operator had excluded through action configuration. Existing action permissions and downstream authorization remain enforced.

    advisories.gitlab.com
  • OSV.devPackage advisoryGHSA-3xr5-8w6c-p5gw

    Backstage: Improper access control in backend action invocation

    osv.dev

References