Plugin auth backend module oidc provider: Backstage: Improper authentication in the OIDC provider (CVE-2026-106488)
Description
A vulnerability in the @backstage/plugin-auth-backend-module-oidc-provider prior to version 0.4.20 allows an authenticated user to impersonate another catalog identity if the OIDC provider permits unverified email addresses. This can lead to unauthorized access and permission escalation. There is no demonstrated impact on availability. A patch is available in version 0.4.20. Workarounds include disabling email-based sign-in resolution or requiring email verification by the identity provider.
CVSS v3.1
Score 8.1high
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in the Backstage plugin @backstage/plugin-auth-backend-module-oidc-provider (CVE-2026-106488) affects deployments using OIDC email-based identity resolution where the provider allows unverified email addresses. An authenticated user can exploit this to assume another user's catalog identity, gaining their access and permissions. The issue does not affect system availability. The vulnerability is patched in version 0.4.20 of the plugin. Mitigations include disabling email-based sign-in resolution or enforcing email verification by the identity provider.
Potential Impact
An authenticated user of the OIDC provider can impersonate another catalog user if the provider permits unverified email addresses, potentially gaining unauthorized access and permissions associated with that user. There is no known impact on system availability.
Mitigation Recommendations
Upgrade to @backstage/plugin-auth-backend-module-oidc-provider version 0.4.20 or later, which contains the official fix. Alternatively, disable email-based sign-in resolution for the OIDC provider or require the identity provider to verify email addresses before allowing sign-in.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-826h-28h9-65hg
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-106488"]
- Ecosystems
- ["npm"]
- Database Specific Severity
- HIGH
- Cvss Version
- 3.1
Threat ID: 6ac6bfff2cdf04f6568291ae
Added to database: 10/07/2026, 21:56:15 UTC
Last enriched: 10/07/2026, 22:14:35 UTC
Last updated: 10/07/2026, 22:14:35 UTC
Views: 6
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