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No exploitation reportedFix available

CVE-2026-106457

Backstage: Insufficient audience validation in the Cloudflare Access auth provider

No exploitation reported by the sources we read.

  • Published2026-10-06
  • Fixed in1.55.0
  • WeaknessCWE-287

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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.

Timeline

dates in UTC
  1. 2026-10-0621:17CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-28 09:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-106457?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-106457?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD · OSV
Linuxfoundation backstage
BranchAffectedFixed in
1.x≥ 1.26.0, < 1.55.01.55.0
Linuxfoundation backstage\/plugin-auth-backend-module-cloudflare-access-provider
BranchAffectedFixed in
0.x≥ 0.1.0, < 0.5.00.5.0

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Vendor advisories

  • CVE-2026-106457 Red Hat Product Security2 known affected

    plugin-auth-backend-module-cloudflare-access-provider: Backstage: Unauthorized access via missing token audience validation

    rhdh/rhdh-hub-rhel9 as a component of Red Hat Developer Hub 1 · ansible-automation-platform/bootc-automation-portal-rhel9 as a component of Self-service automation portal 2

Full record on NVD

Fix

  1. Update Linuxfoundation backstage to 1.55.0
  2. No fix available, says the vendor Red Hat Product Security CVE-2026-106457 · 2 productsFix deferred

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

  • CISA-ADPSSVC decisionnone2026-10-07
  • OpenCVESSVC decisionnone—
  • CNACVSS 3.16.8read 2026-10-28
  • NVDCVSS 3.18.1read 2026-10-28
  • CNAweakness (CWE)CWE-287read 2026-10-28
  • FIRST EPSSEPSS score0.3 %2026-10-26
  • OSVaffected packages—

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Published
2026-10-06
Last Modified
2026-10-27
NVD status
Analyzed

Frequently asked questions

What is CVE-2026-106457?

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.

Is CVE-2026-106457 actively exploited?

Active exploitation of CVE-2026-106457 has not been confirmed. Its EPSS score was 0.3% on 2026-10-26, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-106457?

CVE-2026-106457 has a CVSS v3 base score of 8.1 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N.

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