CVE-2026-106488 is a high-severity (CVSS 8.1) Improper Authentication vulnerability. No vendor fix is recorded yet; mitigation options are listed below.
Backstage is an open framework for building developer portals. Prior to 0.4.20, the @backstage/plugin-auth-backend-module-oidc-provider package is affected by improper authentication…
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-106488.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-106488 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 394,803 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Description
Backstage is an open framework for building developer portals. Prior to 0.4.20, the @backstage/plugin-auth-backend-module-oidc-provider package is affected by improper authentication in the oidc provider. Deployments using OIDC email-based identity resolution with a provider that permits unverified email addresses may allow an authenticated provider user to assume another catalog identity. This may grant access and permissions associated with that user. No direct availability impact is demonstrated. This issue is fixed in version 0.4.20.
Affected Products
backstagelinuxfoundationbackstage\/plugin-auth-backend-module-oidc-providerlinuxfoundationDetection & mitigation playbook
VulnerabilityDetect
Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).
Remediation status
No fixed release is recorded for CVE-2026-106488 yet. Track the upstream advisory, and apply the exposure-reduction steps below in the meantime.
Mitigate without a patch
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Red Hat rates this vulnerability as Important severity because an authenticated remote user can impersonate other catalog accounts and obtain their elevated privileges, leading to significant confidentiality and integrity impact. Exploitation is constrained to environments where OpenID Connect (OIDC) authentication…
To mitigate this vulnerability without code modifications, apply either of the following operational or configuration controls: 1. Configure the external OpenID Connect (OIDC) identity provider to require verified email addresses before permitting user authentication. 2. Reconfigure the portal sign-in resolver to map users using immutable identifiers (such as the provider subject 'sub' claim) rather than email-based claims. Caveats: Enforcing email verification in the identity provider prevents users with unconfirmed addresses from logging in until verification is completed. Modifying sign-in resolver configurations in Red Hat Developer Hub requires restarting the service or container pod,…Source: Red Hat security advisory for CVE-2026-106488 (CC BY 4.0)
Frequently Asked Questions
Is CVE-2026-106488 in your dependencies?
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