CVE-2026-13434: A flaw was found in KubeVirt's network annotation generator

Routine

MEDIUM 4.9WATCHLISTMITIGATEUPGRADE

CVE-2026-13434 is a medium-severity flaw (CVSS 4.9) affecting kubevirt, openshift virtualization. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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. Whe

Why this priority

On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	4.9 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.2% (top 85%)
CISA exploited list	No
Weakness	CWE-20
Published	2026-06-26
Last modified	2026-10-25

Publisher (CNA): Red Hat, Inc. · Vendor: kubevirt · redhat

Last updated 2026-10-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-06-26 17:16 UTCPublished CVE record published
2026-10-25 17:10 UTCUpdated Record last modified

kubevirt kubevirt MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy kubevirt || rpm -q kubevirt || kubevirt --version

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

redhat openshift virtualization UPGRADE

Affected: >= 4 and <= 4.22.0

Fixed in: newer than 4.22.0

Safe to downgrade to: a release before 4

1. Check installed version

apt-cache policy openshift-virtualization || rpm -q openshift-virtualization || openshift-virtualization --version

2. UPGRADE to newer than 4.22.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade openshift-virtualization

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade openshift-virtualization

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 4 (Debian / Ubuntu)

apt-cache madison openshift-virtualization sudo apt install openshift-virtualization=<VERSION_BEFORE_4> sudo apt-mark hold openshift-virtualization

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list openshift-virtualization sudo dnf downgrade openshift-virtualization-<VERSION_BEFORE_4> sudo dnf versionlock add openshift-virtualization

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-13434?

kubevirt: mitigate or apply the listed mitigation; openshift virtualization: upgrade to newer than 4.22.0. Exact commands for each OS are on this page.

Is CVE-2026-13434 being exploited?

CVE-2026-13434 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-13434 affect?

CVE-2026-13434 affects kubevirt, openshift virtualization. Severity is medium (CVSS 4.9). 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/def

How urgent is CVE-2026-13434?

Priority 26/100. On your watchlist

Software pages

Red Hat OpenShift vulnerabilities

References

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