EUVD-2026-38233
GHSA-x82v-328r-gf3h
Severity by source
AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Attacker needs local access to a compromised Windows node with WICD credentials (AV:L, PR:L); auto-approver flaw reliably yields cluster-admin, causing scope change and full CIA impact.
Primary rating from Vendor (redhat).
CVSS VectorVendor: redhat
Lifecycle Timeline
2DescriptionCVE.org
A flaw was found in the Windows Machine Config Operator (WMCO) for Red Hat OpenShift Container Platform. The WICD CSR auto-approver validates that a Certificate Signing Request contains the organization system:wicd-nodes but does not reject additional organization values such as system:masters. A compromised Windows worker node that holds WICD credentials can submit a CSR that is auto-approved and signed by the cluster, yielding a client certificate that grants cluster-administrator privileges and enabling full cluster takeover.
AnalysisAI
Privilege escalation in the Windows Machine Config Operator (WMCO) for Red Hat OpenShift Container Platform allows a compromised Windows worker node holding WICD credentials to obtain a cluster-administrator client certificate. The WICD CSR auto-approver checks for the system:wicd-nodes organization but fails to reject additional organization values such as system:masters, enabling full cluster takeover. No public exploit identified at time of analysis, and the issue is not listed in CISA KEV.
Technical ContextAI
OpenShift's WMCO manages Windows worker nodes joining a Kubernetes cluster, and the Windows Instance Config Daemon (WICD) uses Kubernetes Certificate Signing Requests (CSRs) to enroll node identities. An auto-approver controller signs CSRs containing the system:wicd-nodes organization, but Kubernetes uses the certificate's Organization (O) field to populate group membership during RBAC evaluation, and system:masters is a built-in superuser group bound to cluster-admin. The root cause maps to CWE-269 (Improper Privilege Management): the approver applies an allowlist check on one O value without enforcing that no other privileged groups are present. Affected CPEs cover Red Hat OpenShift Container Platform 4 and Red Hat OpenShift for Windows Containers.
RemediationAI
Patch availability per vendor advisory - apply the Red Hat-supplied WMCO update for your OpenShift 4 channel as described at https://access.redhat.com/security/cve/CVE-2026-54099 once the fixed WMCO version is published, and track https://bugzilla.redhat.com/show_bug.cgi?id=2487950 for version specifics. As compensating controls until patched, harden Windows worker nodes to prevent theft of WICD credentials (restrict local administrator access, enforce node-level EDR, and rotate node credentials), audit pending and recently approved CSRs for organization fields containing system:masters or any value other than system:wicd-nodes, and consider temporarily disabling the WICD CSR auto-approver and approving CSRs manually - the trade-off is increased operational toil when scaling Windows node pools. Review audit logs for any clusterrolebinding or token usage tied to certificates issued with the system:masters group.
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Same weakness CWE-269 – Improper Privilege Management
View allSame technique Privilege Escalation
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