Backstage: Insufficient audience validation in the Cloudflare Access auth provider
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.
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