Red Hat Red Hat Container Native Virtualization 4.18 vulnerabilities

A symlink following vulnerability was found in KubeVirt's virt-handler migration proxy. During live migration, virt-handler dials Unix sockets inside the target virt-launcher pod via /proc/<pid>/root/ paths using net.Dial() without symlink protection. These socket paths reside in qemu-owned directories writable by the virt-launcher user. An attacker with namespace edit and pods/exec permissions can replace a migration proxy socket with a symlink to the host CRI-O socket. Because virt-handler runs as root in the host mount namespace, absolute symlink targets resolve against the host filesystem, and the bidirectional io.Copy proxy relays attacker-controlled bytes to the container runtime, enabling full node compromise.

In containerized-data-importer (CDI), the aggregated cdi.kubevirt.io:view ClusterRole, intended to provide read-only access to CDI resources, includes a rule granting create on the datavolumes/source subresource. CDI's DataVolume clone authorization accepts this permission as sufficient to authorize cloning the contents of any PVC the caller can name, without requiring write access to the source namespace. A user or service account bound to the view role, commonly granted cluster-wide via ClusterRoleBinding, who also has ordinary write access (edit/admin) to any single namespace, can use this to exfiltrate the contents of any PVC in the cluster into a namespace they control, bypassing namespace isolation and the read-only guarantee of the view role.

A flaw was found in KubeVirt's safepath package used by virt-handler. The OpenAtNoFollow function uses O_PATH|O_NOFOLLOW to obtain a file descriptor to a path leaf, but downstream operations resolve the path via /proc/self/fd/N using link-following syscalls. When the leaf is a symlink, the kernel dereferences it, defeating the intended no-follow protection. An attacker with access to a virt-launcher pod can exploit this to redirect virt-handler's IPC socket connections, including the notify socket used for VM domain lifecycle events. By hijacking this socket, the attacker can inject arbitrary domain events into virt-handler, causing it to take incorrect lifecycle actions, corrupt VM state in the Kubernetes API, or crash — resulting in sustained denial of VM management services for all virtual machines on the affected node. Additionally, the same symlink following flaw allows virt-handler to apply file ownership or permission changes to unintended host paths.

A flaw was found in KubeVirt's virt-exportserver component. An attacker with specific namespace-level access can exploit a path traversal vulnerability in the VMExport directory endpoint. By placing a symbolic link (symlink) within an exported filesystem Persistent Volume Claim (PVC) that points outside its designated mount root, the attacker can read arbitrary files from the exporter pod's filesystem. This leads to information disclosure, potentially exposing sensitive data.