CVE-2026-6383

In KubeVirt, an authenticated user with permission to create Virtual Machine Instances (VMIs) can cause a Denial of Service (DoS) by submitting a virtual machine definition with an empty ephemeral volume. The virt-controller component fails to properly validate the volume configuration, leading to an unhandled exception and application crash during processing. Because the malformed definition persists in the cluster, the controller enters a continuous crash loop, disrupting virtual machine lifecycle operations across the entire environment.

A flaw was found in KubeVirt's virt-handler component due to improper symlink validation when connecting to virtual machine console sockets. An authenticated OpenShift user with edit permissions in a single namespace can replace the console socket with a symlink to the host's CRI-O socket, hijacking virt-handler's privileged connection.

A symlink following vulnerability 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 without symlink protection. An attacker with namespace edit and pods/exec permissions can replace a migration proxy socket with a symlink to the host CRI-O socket, enabling full node compromise.

A flaw in KubeVirt's network annotation generator allows a tenant with kubevirt.io:edit permissions to inject JSON into the v1.multus-cni.io/default-network annotation due to missing validation. When the ExternalNetResourceInjection feature gate is enabled (off by default), Multus can attach the pod to any network in any namespace.

A flaw was found in KubeVirt's downward metrics virtio-serial server. The server reads guest requests using textproto.Reader.ReadLine(), which buffers input indefinitely until a newline character is received, with no length limit or read deadline. A user with access to a VM guest that has the downward metrics virtio-serial device configured can write a continuous byte stream to the device, causing unbounded memory allocation in the virt-handler process until it is OOM-killed.

A server-side request forgery (SSRF) flaw was found in KubeVirt's virt-api port-forward handler. When processing a port-forward request to a VirtualMachineInstance (VMI), virt-api reads the target IP from vmi.Status.Interfaces[0].IP and passes it directly to net.Dial() without validation. For VMIs using non-masquerade network bindings (bridge or secondary-only), this IP is reported by the QEMU guest agent running inside the VM and is fully controllable by the VM owner.

A flaw in KubeVirt's virt-handler network cache handling allows a user with access to the virt-launcher container to overwrite arbitrary host files with JSON content and change their ownership by planting a symlink at the cache file path.

A flaw was found in KubeVirt's virt-handler domain notify server. The gRPC handlers for HandleDomainEvent and HandleK8SEvent derive the VMI identity (namespace/name) solely from the request body without validating it against the connection's origin. Each virt-launcher pod connects through a per-VMI pipe socket, but no identity tag is propagated from the pipe path to the server handlers.

A flaw in KubeVirt's safepath package, used by virt-handler, was found in the OpenAtNoFollow function. It uses O_PATH|O_NOFOLLOW to obtain a file descriptor, but subsequent operations resolve the path via /proc/self/fd/N using link-following syscalls. When the leaf is a symlink, the kernel dereferences it, bypassing the intended no-follow protection.

A path traversal vulnerability was found in KubeVirt's virt-exportserver component. An attacker with namespace-level access can place a symbolic link in an exported PVC pointing outside its mount root, allowing arbitrary file reads from the exporter pod's filesystem.