CVE-2026-13318

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 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.

A flaw in KubeVirt's Role-Based Access Control (RBAC) evaluation logic improperly truncates subresource names, leading to incorrect permission evaluations. Authenticated users with specific custom roles may gain unauthorized access to subresources or be wrongly denied access.