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CVE-2026-106457

high

Backstage is an open framework for building developer portals.

Vendor / product: 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.

CVSS
8.1
8.1 (CVSS v3.1)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Severity source: NVD CVSS v3.1 (nvd@nist.gov)
Timeline (UTC)
Published: 2026-10-06 21:17
Modified: 2026-10-27 20:48
NVD status: Analyzed
Last synced 19 hours ago
Verified against the source API 2026-10-28 11:30 UTC
Exploitation
Not listed in CISA KEV (as of last catalog sync)
Absence from KEV does not mean a CVE is not exploited. Exploitation status: unknown (no authoritative evidence in our sources).

Affected products

linuxfoundation / backstage\/plugin-auth-backend-module-cloudflare-access-provider ≥0.1.0 <0.5.0
linuxfoundation / backstage ≥1.26.0 <1.55.0

Weakness classification (CWE)

Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.

Mitigation & advisories

Vendor advisory: https://github.com/backstage/backstage/security/advisories/GHSA-q333-f498-w2x7
Patch / mitigation: https://github.com/backstage/backstage/commit/ed9034cacd9def3b3674f0a764fe992f751e204d
Patch / mitigation: https://github.com/backstage/backstage/releases/tag/v1.55.0
Patch / mitigation: https://github.com/backstage/backstage/security/advisories/GHSA-q333-f498-w2x7

References

Data sources

NVD CVE API 2.0 — fetched 2026-10-28 11:30 UTC · record ↗

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