CVE-2026-13322

Kubevirt: virt-handler-rhel9: kubevirt: unbounded virtio-serial readline in virt-handler causes oom denial of service

Published Jun 26, 2026 CVSS 3.1 · 3.8 Low EPSS < 1% KEV · Not listed
Description
A flaw was found in KubeVirt's downward metrics virtio-serial server. The server reads guest requests using textproto.Reader.ReadLine(), which buffers input indefinitely until a newline character is received, with no length limit or read deadline. A user with access to a VM guest that has the downward metrics virtio-serial device configured can write a continuous byte stream to the device, causing unbounded memory allocation in the virt-handler process until it is OOM-killed.

Remediation

Vendor Workaround

The downward metrics virtio-serial device must be explicitly added to a VM's specification to be present. Clusters that do not use this feature are not exposed. To reduce exposure, administrators can restrict the ability to configure downward metrics devices on tenant VMs by using an admission webhook or policy controller such as Gatekeeper/OPA.

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-6f2p-2qg2-qqch KubeVirt downward metrics virtio-serial server vulnerable to unbounded memory consumption
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Kubevirt
Kubevirt kubevirt
Redhat openshift Virtualization
Vendors & Products Kubevirt
Kubevirt kubevirt
Redhat openshift Virtualization
Type Values Removed Values Added
Description A flaw was found in KubeVirt's downward metrics virtio-serial server. The server reads guest requests using textproto.Reader.ReadLine(), which buffers input indefinitely until a newline character is received, with no length limit or read deadline. A user with access to a VM guest that has the downward metrics virtio-serial device configured can write a continuous byte stream to the device, causing unbounded memory allocation in the virt-handler process until it is OOM-killed.
Title Kubevirt: virt-handler-rhel9: kubevirt: unbounded virtio-serial readline in virt-handler causes oom denial of service
First Time appeared Redhat
Redhat container Native Virtualization
Weaknesses CWE-770
CPEs cpe:/a:redhat:container_native_virtualization:4
Vendors & Products Redhat
Redhat container Native Virtualization
References
Metrics threat_severity

None

cvssV3_1

{'score': 3.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:L'}

threat_severity

Low

Weaknesses

Sources

Status
PUBLISHED
Assigner
redhat
Published
Updated
Jun 26, 2026, 1:39 PM
Reserved
Jun 25, 2026, 8:58 AM
Status
Analyzed
Published
Jun 26, 2026, 12:16 AM
Modified
Oct 25, 2026, 10:10 PM
Severity
Low
Public date
Jun 25, 2026, 12:00 AM