CVE-2026-13434
Virt-controller-rhel9: kubevirt: kubevirt: multus default-network annotation injection via unvalidated tenant networkname when externalnetresourceinjection is enabled
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).
INFO
Published Date :
June 26, 2026, 5:16 p.m.
Last Modified :
July 6, 2026, 5:51 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-13434
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | 53f830b8-0a3f-465b-8143-3b8a9948e749 | ||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Disable the ExternalNetResourceInjection feature gate.
- Restrict 'kubevirt.io:edit' permissions.
- Validate network names for proper format.
- Update KubeVirt to the latest version.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-13434.
| URL | Resource |
|---|---|
| https://access.redhat.com/security/cve/CVE-2026-13434 | Mitigation Vendor Advisory |
| https://bugzilla.redhat.com/show_bug.cgi?id=2493576 | Vendor Advisory Issue Tracking |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-13434 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-13434
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-13434 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-13434 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Jul. 06, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:kubevirt:kubevirt:-:*:*:*:*:kubernetes:*:* *cpe:2.3:a:redhat:openshift_virtualization:*:*:*:*:*:*:*:* versions from (including) 4 up to (including) 4.22.0 Added Reference Type Red Hat, Inc.: https://access.redhat.com/security/cve/CVE-2026-13434 Types: Mitigation, Vendor Advisory Added Reference Type Red Hat, Inc.: https://bugzilla.redhat.com/show_bug.cgi?id=2493576 Types: Issue Tracking, Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 27, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-13434', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-06-27T02:38:10.829887Z'} -
New CVE Received by [email protected]
Jun. 26, 2026
Action Type Old Value New Value Added Affected [{'cpes': ['cpe:/a:redhat:container_native_virtualization:4'], 'vendor': 'Red Hat', 'product': 'Red Hat OpenShift Virtualization 4', 'packageName': 'container-native-virtualization/virt-controller-rhel9', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'affected'}] Added 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). Added CVSS V3.1 AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:N Added CWE CWE-20 Added Reference https://access.redhat.com/security/cve/CVE-2026-13434 Added Reference https://bugzilla.redhat.com/show_bug.cgi?id=2493576