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CVE-2026-13322 Red Hat CVE debrief

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.

Vendor
Red Hat
Product
Red Hat OpenShift Virtualization 4
CVSS
LOW 3.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-26
Original CVE updated
2026-07-06
Advisory published
2026-06-26
Advisory updated
2026-07-06

Who should care

Users of KubeVirt, especially those with administrative access to VM guests configured with the downward metrics virtio-serial device, should be aware of this vulnerability and take steps to mitigate it.

Technical summary

The KubeVirt downward metrics virtio-serial server is vulnerable to an issue where it reads guest requests using textproto.Reader.ReadLine(). This method buffers input indefinitely until a newline character is received, with no length limit or read deadline. An attacker with access to a VM guest configured with the downward metrics virtio-serial device can exploit this by writing a continuous byte stream to the device. This can cause unbounded memory allocation in the virt-handler process, potentially leading to the process being OOM-killed.

Defensive priority

Medium

Recommended defensive actions

  • Update KubeVirt to a version that includes a fix for this issue.
  • Restrict access to VM guests configured with the downward metrics virtio-serial device.
  • Monitor virt-handler process memory usage for anomalies.
  • Implement compensating controls to limit the impact of potential memory exhaustion.
  • Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.

Evidence notes

The CVE record was published on 2026-06-26T00:16:51.397Z and was last modified on 2026-07-06T17:25:39.853Z. The NVD entry is currently Analyzed. References include vendor advisories and issue tracking links.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-13322 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-13322

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-13322 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-13322

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.