← Vulnerability feed

Vulnerability record · CVE-2026-13434 · published 26 June 2026

CVE-2026-13434: Kubevirt improper input validation vulnerability

Kubevirt · Kubevirt

A flaw was found in KubeVirt's network annotation generator. When a tenant creates a VirtualMachineInstance with a Multus network configuration, the supplied networkName value is written verbatim into the launcher pod's v1.multus-cni.io/default-network annotation without format validation or sanitization. The only admission check rejects empty strings; no DNS-1123 format validation, JSON detection, or special character rejection is performed. When the ExternalNetResourceInjection Beta feature gate is enabled (off by default, cluster-admin only), the NAD lookup that would otherwise catch malformed names is skipped by design. A tenant with kubevirt.io:edit permissions can inject a JSON-formatted NetworkSelectionElement array specifying an arbitrary namespace, NAD name, static IP address, and MAC address. Multus on the node parses this JSON and attaches the launcher pod to the specified network attachment in any namespace, enabling cross-namespace network access and IP/MAC impersonation on network segments normally segregated from tenant workloads. The ExternalNetResourceInjection feature gate was introduced in KubeVirt v1.8.0 (first shipped in OpenShift Virtualization 4.21).

4.9 CVSS 3.1 Medium EPSS 0.24% · top 85.9% CWE-20 · Improper input validation
4.9CVSS 3.1 base score
0.24%EPSS exploitation probability, 30 days
NoNot in CISA KEV
2Affected product versions listed by NVD
2References
6 Jul 2026Last modified by NVD

Description

A flaw was found in KubeVirt's network annotation generator. When a tenant creates a VirtualMachineInstance with a Multus network configuration, the supplied networkName value is written verbatim into the launcher pod's v1.multus-cni.io/default-network annotation without format validation or sanitization. The only admission check rejects empty strings; no DNS-1123 format validation, JSON detection, or special character rejection is performed. When the ExternalNetResourceInjection Beta feature gate is enabled (off by default, cluster-admin only), the NAD lookup that would otherwise catch malformed names is skipped by design. A tenant with kubevirt.io:edit permissions can inject a JSON-formatted NetworkSelectionElement array specifying an arbitrary namespace, NAD name, static IP address, and MAC address. Multus on the node parses this JSON and attaches the launcher pod to the specified network attachment in any namespace, enabling cross-namespace network access and IP/MAC impersonation on network segments normally segregated from tenant workloads. The ExternalNetResourceInjection feature gate was introduced in KubeVirt v1.8.0 (first shipped in OpenShift Virtualization 4.21).

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:N

Affected products

2 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://access.redhat.com/security/cve/CVE-2026-13434 MitigationVendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2493576 Vendor AdvisoryIssue Tracking

Track CVE-2026-13434 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

Start free Open in platform

Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

7.5CVE-2023-44487HTTP/2 Rapid Reset stream cancellation denial of serviceThe HTTP/2 protocol permits a client to cancel many streams quickly, and the server's handling of those resets consumes disproportionate resources. T…KEVEPSS 100%analysed9.9CVE-2020-14316Kubevirt vulnerabilityA flaw was found in kubevirt 0.29 and earlier. Virtual Machine Instances (VMIs) can be used to gain access to the host's filesystem. Successful explo…EPSS 1.6%8.5CVE-2025-64324Kubevirt information exposure vulnerabilityKubeVirt is a virtual machine management add-on for Kubernetes. The `hostDisk` feature in KubeVirt allows mounting a host file or directory owned by …EPSS 0.22%8.2CVE-2023-26484Kubevirt incorrect authorization vulnerabilityKubeVirt is a virtual machine management add-on for Kubernetes. In versions 0.59.0 and prior, if a malicious user has taken over a Kubernetes node wh…EPSS 0.61%7.7CVE-2026-44495Axios code injection vulnerabilityAxios is a promise based HTTP client for the browser and Node.js. From 0.19.0 to before 0.31.1 and 1.15.2, Axios contains prototype-pollution gadgets…EPSS 1.0%7.3CVE-2026-13201Kubevirt vulnerabilityA 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 …EPSS 0.27%7.0CVE-2020-1742Kubernetes-nmstate incorrect permission assignment vulnerabilityAn insecure modification vulnerability flaw was found in containers using nmstate/kubernetes-nmstate-handler. An attacker with access to the containe…EPSS 0.26%6.9CVE-2025-64436Kubevirt improper privilege management vulnerabilityKubeVirt is a virtual machine management add-on for Kubernetes. In 1.5.0 and earlier, the permissions granted to the virt-handler service account, su…EPSS 0.26%

Source: NIST National Vulnerability Database (record CVE-2026-13434), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.