Virt-controller-rhel9: kubevirt: kubevirt: multus default-network annotation injection via unvalidated tenant networkname when externalnetresourceinjection is enabled
Summary
| CVE | CVE-2026-13434 |
|---|---|
| State | PUBLISHED |
| Assigner | redhat |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-06-26 17:16:32 UTC |
| Updated | 2026-06-26 17:16:32 UTC |
| 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). |
Risk And Classification
Primary CVSS: v3.1 4.9 MEDIUM from [email protected]
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:N
Problem Types: CWE-20 | CWE-20 Improper Input Validation
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Primary | 4.9 | MEDIUM | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:N |
| 3.1 | CNA | CVSS | 4.9 | MEDIUM | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:N |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
HighPrivileges Required
LowUser Interaction
NoneScope
ChangedConfidentiality
LowIntegrity
LowAvailability
NoneCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:N
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Red Hat | Red Hat OpenShift Virtualization 4 | Not specified | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| access.redhat.com/security/cve/CVE-2026-13434 | [email protected] | access.redhat.com | |
| bugzilla.redhat.com/show_bug.cgi | [email protected] | bugzilla.redhat.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: This issue was discovered by Huzaifa Sidhpurwala (Red Hat). (en)
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| CNA | 2026-06-26T00:00:00.000Z | Reported to Red Hat. |
| CNA | 2026-06-26T00:00:00.000Z | Made public. |
Workarounds
CNA: If the ExternalNetResourceInjection feature gate has been enabled, disable it by removing it from the HyperConverged CR's spec.featureGates configuration. This restores the NAD lookup that blocks malformed network names. If the feature gate is required for operational reasons, restrict kubevirt.io:edit permissions to trusted users only and enforce NetworkPolicy on sensitive network segments to limit lateral movement from unauthorized attachments.
There are currently no legacy QID mappings associated with this CVE.