CVE-2026-9804

Vulnerability

CVE-2026-9804 is a path traversal vulnerability in the virt-exportserver component of KubeVirt. The VMExport directory endpoint uses Go's http.FileServer(http.Dir(mountPoint)) to serve the contents of a filesystem Persistent Volume Claim (PVC). Because http.Dir follows symbolic links, an attacker who can control files inside an exported filesystem PVC can place a symlink pointing outside the PVC mount root and read arbitrary files from the exporter pod's filesystem through the directory endpoint. This vulnerability affects filesystem PVCs that do not have the cdi.kubevirt.io/storage.contentType annotation set to a KubeVirt content type. PVCs with KubeVirt content type receive raw/gzip export endpoints instead of the vulnerable directory endpoint [1][2].

Exploitation

To exploit this vulnerability, an attacker must have namespace-level access sufficient to create or control the contents of a filesystem PVC. The attacker needs to create a VirtualMachineExport resource for that PVC and possess or obtain the VMExport token. The attacker then embeds a symbolic link within the exported PVC that points to a target file outside the mount root. When the token is used to access the exported directory, the virt-exportserver follows the symlink and serves the targeted file, which resides on the exporter pod's filesystem [2]. Namespaces with mixed workloads (pods and VMs) are more likely to have affected PVCs than namespaces hosting only KubeVirt VMs [2].

Impact

Successful exploitation allows an attacker to read arbitrary files from the exporter pod's filesystem, leading to information disclosure. This can potentially expose sensitive data such as secrets, configuration files, or other confidential information stored within the pod [1][2].

Mitigation

Red Hat has not yet published a specific fixed version for this vulnerability. Users are advised to ensure that filesystem PVCs used with VMs have the cdi.kubevirt.io/storage.contentType annotation set to an appropriate KubeVirt content type, which causes the export endpoint to be raw/gzip instead of the vulnerable directory endpoint. Additionally, restrict namespace-level access to prevent unauthorized users from creating or modifying PVCs or VirtualMachineExport resources [1][2].