Skip to content
Heist/ feed
Medium

Backstage: Insufficient audience validation in the Cloudflare Access auth provider

Type: advisorySource: Official CVE List1 source record

Backstage is an open framework for building developer portals. From 0.1.0 until 0.5.0, the @backstage/plugin-auth-backend-module-cloudflare-access-provider package is affected by insufficient audience validation in the cloudflare access auth provider. The Cloudflare Access auth provider verifies a token's signature and team issuer, but affected versions do not verify that the token was issued for the Backstage application. A user holding a valid token for another Access application in the same Cloudflare Zero Trust team may therefore be able to authenticate to Backstage if that token reaches the auth endpoint without the Backstage application's audience already being enforced upstream. Cloudflare Access normally evaluates the protected application before forwarding requests. This issue is fixed in version 0.5.0.

Announced Source revision 1
Original source ↗

CVE-2026-106457

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-106457

backstage

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

plugin-auth-backend-module-cloudflare-access-provider

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "vendor": "backstage",
    "product": "backstage",
    "versions": [
      {
        "status": "affected",
        "version": ">= 1.26.0, < 1.55.0"
      }
    ]
  },
  {
    "vendor": "@backstage",
    "product": "plugin-auth-backend-module-cloudflare-access-provider",
    "versions": [
      {
        "status": "affected",
        "version": ">= 0.1.0, < 0.5.0"
      }
    ]
  }
]
Related CVEs
CVE-2026-106457

Source reference: /cveMetadata/cveId

Publisher severity

medium

Source reference: /containers/cna/metrics

Event
#11904 · Revision 1
Added to Heist Feed
Publisher date
Read the original announcement