EUVD-2026-38234
GHSA-q3jf-4x8j-368q
Severity by source
AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
Adjacent-network MITM on SSH bootstrap (AV:A, AC:H), no auth needed (PR:N), no user interaction, and captured node credentials cross a trust boundary into the cluster (S:C) with full CIA impact on Windows workloads.
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. WMCO establishes SSH connections to Windows worker nodes without verifying the remote server host key. An adjacent-network attacker who can intercept or redirect WMCO's SSH session can capture WICD and kubelet bootstrap credentials transferred during node configuration, enabling compromise of Windows node identities in the cluster.
AnalysisAI
Credential theft in Red Hat OpenShift Container Platform's Windows Machine Config Operator (WMCO) allows adjacent-network attackers to intercept SSH sessions to Windows worker nodes and steal WICD and kubelet bootstrap credentials. WMCO fails to verify the remote SSH host key when configuring Windows nodes, enabling a man-in-the-middle attacker positioned on the cluster network to capture credentials sufficient to assume Windows node identities. No public exploit identified at time of analysis, and the issue is not in CISA KEV.
Technical ContextAI
The vulnerability sits in the Windows Machine Config Operator (WMCO), the OpenShift component responsible for joining Windows Server worker nodes into a predominantly Linux-based OpenShift cluster (cpe red_hat_openshift_for_windows_containers and red_hat_openshift_container_platform_4). During node bootstrap, WMCO opens an SSH connection to each Windows node to transfer the Windows Instance Config Daemon (WICD) binary and kubelet bootstrap kubeconfig. The flaw is a classic CWE-295 (Improper Certificate/Key Validation) - specifically, the SSH client is configured to accept any host key (equivalent to StrictHostKeyChecking=no with no known_hosts pinning), so it cannot distinguish the legitimate Windows node from an attacker-controlled SSH endpoint on the same L2/L3 segment.
RemediationAI
Patch available per vendor advisory - upgrade WMCO to the fixed version published by Red Hat for your OpenShift 4.x stream as referenced in https://access.redhat.com/security/cve/CVE-2026-54100 (exact fix version not enumerated in the input data, so verify against the Red Hat errata before rollout). Until patched, restrict layer-2 and layer-3 access to the Windows node bootstrap network so only the OpenShift control plane can reach Windows nodes on TCP/22 (this may break troubleshooting SSH access from jump hosts), avoid bootstrapping new Windows nodes on shared or untrusted networks, and rotate any WICD and kubelet bootstrap credentials issued to Windows nodes that were configured before the fix was applied since they may already be compromised. Enabling stricter network policies and segmenting the machine network from tenant workload networks reduces the adjacent-attacker population at the cost of more complex CNI configuration.
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Same weakness CWE-295 – Improper Certificate Validation
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