CVE-2026-106460: Backstage: Explicit negative email verification can be ignored during shared OAuth profile normalization

Severity: medium (CVSS 6.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-06 · updated 2026-10-27
Weakness: CWE-287

Description

Backstage is an open framework for building developer portals. From 0.3.0 until 0.6.15 and 0.7.5, the @backstage/plugin-auth-node package did not consistently honor explicit negative email verification during shared OAuth profile normalization. The affected paths include a selected profile email marked verified: false, a matching raw provider email marked email_verified: false, and an email obtained only from an ID token marked email_verified: false. Exploitation requires an admitted identity-provider user who can supply or change an unverified email and a deployment that uses the selected profile email to resolve catalog identities. The verification metadata must apply to the selected email; an absent email_verified claim alone is not affected. In an affected configuration, the user may assume another catalog identity and obtain its associated access and permissions. This issue is fixed in versions 0.6.15 and 0.7.5.

Affected products

backstage: from 0.4.0 before 0.5.15 — fixed in 0.5.15
Linuxfoundation Backstage/Plugin-Auth-Node: from 0.3.0 before 0.6.15; from 0.7.0 before 0.7.5 — fixed in 0.6.15, 0.7.5
backstage: from 1.18.0, < 1.49.7; from 1.50.0-next.0, < 1.54.7
@backstage plugin-auth-node: from 0.3.0, < 0.6.15; from 0.7.0, < 0.7.5

How to fix

Upgrade to a fixed version: backstage 0.5.15; Linuxfoundation Backstage/Plugin-Auth-Node 0.6.15, 0.7.5. Check the vendor advisory for mitigations.

References

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