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Vulnerabilities

Security fix · CVE-2026-106457

Backstage is an open framework for building developer portals.

Published Oct 6, 2026 · catalog updated Oct 27, 2026 · Backstage is an open

Last checked Oct 28, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-106457. EPSS is 0.28%. Act only if a listed version of Backstage is an open is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Backstage is an open).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High8.1
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.28%
Remediation
Version ranges on file
Affected products
cpe linuxfoundation/backstage · cpe linuxfoundation/backstage/plugin-auth-backend-module-cloudflare-access-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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe linuxfoundation/backstage< 1.55.0
  • cpe linuxfoundation/backstage/plugin-auth-backend-module-cloudflare-access-provider< 0.5.0

How to fix CVE-2026-106457

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-106457. EPSS is 0.28%. Act only if a listed version of Backstage is an open is installed.

Which versions are affected?

Compare what you have installed with < 1.55.0, < 0.5.0. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-287: Improper Authentication. EPSS 0.28%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

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

Timeline

Detection, updates, and resolution for this record.

  1. Oct 6, 2026 · NIST NVD

    Detected

    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

  2. Oct 27, 2026 · NIST NVD

    Updated

    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

Sources

  • CVE.orgVulnerability recordCVE-2026-106457

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-106457

    30-day exploitation probability 0.28%

    first.org
  • NIST NVDVulnerability recordCVE-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 p

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 28, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSOct 28, 2026
  • CVE.orgOct 28, 2026
  • NIST NVDOct 28, 2026