4.9
MEDIUM CVSS 3.1
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 !
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.

ID Vendor Product Action
1 Redhat openshift_virtualization
1 Kubevirt kubevirt
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
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 ExternalNetResourceInjection feature or restrict editing permissions to prevent network annotation manipulation.
  • 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.

CAPEC-3: Using Leading 'Ghost' Character Sequences to Bypass Input Filters Using Leading 'Ghost' Character Sequences to Bypass Input Filters CAPEC-7: Blind SQL Injection Blind SQL Injection CAPEC-8: Buffer Overflow in an API Call Buffer Overflow in an API Call CAPEC-9: Buffer Overflow in Local Command-Line Utilities Buffer Overflow in Local Command-Line Utilities CAPEC-10: Buffer Overflow via Environment Variables Buffer Overflow via Environment Variables CAPEC-13: Subverting Environment Variable Values Subverting Environment Variable Values CAPEC-14: Client-side Injection-induced Buffer Overflow Client-side Injection-induced Buffer Overflow CAPEC-22: Exploiting Trust in Client Exploiting Trust in Client CAPEC-23: File Content Injection File Content Injection CAPEC-24: Filter Failure through Buffer Overflow Filter Failure through Buffer Overflow CAPEC-28: Fuzzing Fuzzing CAPEC-31: Accessing/Intercepting/Modifying HTTP Cookies Accessing/Intercepting/Modifying HTTP Cookies CAPEC-42: MIME Conversion MIME Conversion CAPEC-43: Exploiting Multiple Input Interpretation Layers Exploiting Multiple Input Interpretation Layers CAPEC-45: Buffer Overflow via Symbolic Links Buffer Overflow via Symbolic Links CAPEC-46: Overflow Variables and Tags Overflow Variables and Tags CAPEC-47: Buffer Overflow via Parameter Expansion Buffer Overflow via Parameter Expansion CAPEC-52: Embedding NULL Bytes Embedding NULL Bytes CAPEC-53: Postfix, Null Terminate, and Backslash Postfix, Null Terminate, and Backslash CAPEC-63: Cross-Site Scripting (XSS) Cross-Site Scripting (XSS) CAPEC-64: Using Slashes and URL Encoding Combined to Bypass Validation Logic Using Slashes and URL Encoding Combined to Bypass Validation Logic CAPEC-67: String Format Overflow in syslog() String Format Overflow in syslog() CAPEC-71: Using Unicode Encoding to Bypass Validation Logic Using Unicode Encoding to Bypass Validation Logic CAPEC-72: URL Encoding URL Encoding CAPEC-73: User-Controlled Filename User-Controlled Filename CAPEC-78: Using Escaped Slashes in Alternate Encoding Using Escaped Slashes in Alternate Encoding CAPEC-79: Using Slashes in Alternate Encoding Using Slashes in Alternate Encoding CAPEC-80: Using UTF-8 Encoding to Bypass Validation Logic Using UTF-8 Encoding to Bypass Validation Logic CAPEC-81: Web Server Logs Tampering Web Server Logs Tampering CAPEC-83: XPath Injection XPath Injection CAPEC-85: AJAX Footprinting AJAX Footprinting CAPEC-88: OS Command Injection OS Command Injection CAPEC-101: Server Side Include (SSI) Injection Server Side Include (SSI) Injection CAPEC-104: Cross Zone Scripting Cross Zone Scripting CAPEC-108: Command Line Execution through SQL Injection Command Line Execution through SQL Injection CAPEC-109: Object Relational Mapping Injection Object Relational Mapping Injection CAPEC-110: SQL Injection through SOAP Parameter Tampering SQL Injection through SOAP Parameter Tampering CAPEC-120: Double Encoding Double Encoding CAPEC-135: Format String Injection Format String Injection CAPEC-136: LDAP Injection LDAP Injection CAPEC-153: Input Data Manipulation Input Data Manipulation CAPEC-182: Flash Injection Flash Injection CAPEC-209: XSS Using MIME Type Mismatch XSS Using MIME Type Mismatch CAPEC-230: Serialized Data with Nested Payloads Serialized Data with Nested Payloads CAPEC-231: Oversized Serialized Data Payloads Oversized Serialized Data Payloads CAPEC-250: XML Injection XML Injection CAPEC-261: Fuzzing for garnering other adjacent user/sensitive data Fuzzing for garnering other adjacent user/sensitive data CAPEC-267: Leverage Alternate Encoding Leverage Alternate Encoding CAPEC-473: Signature Spoof Signature Spoof CAPEC-588: DOM-Based XSS DOM-Based XSS CAPEC-664: Server Side Request Forgery Server Side Request Forgery

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
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.