Executive brief
The Windows Machine Config Operator (WMCO) is a component of Red Hat OpenShift used to manage and configure Windows-based worker nodes within a cluster. A security flaw allows an attacker on the same local network to intercept the setup process because the system fails to verify the identity of the Windows nodes it connects to. This could allow an attacker to steal administrative credentials, potentially leading to a full takeover of the Windows nodes and compromising the security of the entire container platform.
Technical details
A flaw exists in the Windows Machine Config Operator (WMCO) due to improper validation of SSH host keys (CWE-295) during the node reconciliation process. When WMCO establishes SSH connections to Windows worker nodes to perform configuration tasks, it does not verify the remote server's identity. An attacker positioned on an adjacent network can perform a man-in-the-middle (MitM) attack to intercept or redirect these SSH sessions. By impersonating a legitimate node, the attacker can capture WICD and kubelet bootstrap credentials transferred during configuration, leading to the compromise of Windows node identities within the OpenShift cluster. This vulnerability requires the attacker to be on the same network segment as the WMCO or the target nodes.
Affected products
- Red Hat OpenShift Container Platform 4 4
- Red Hat OpenShift for Windows Containers 4
- Red Hat Windows Machine Config Operator (WMCO)
Timeline
- 2026-06-11: disclosed: Initial report in Red Hat Bugzilla
- 2026-06-22: advisory: NVD and Red Hat published advisory details