Medium

CVE-2026-13218 — Kubevirt: kubevirt: symlink following in writetocachedfile allows host file overwrite from virt-launcher

A flaw was found in KubeVirt's virt-handler network cache handling. The WriteToCachedFile function writes data to a launcher-rooted path using os.WriteFile and os.Chown without symlink protection. A user with access to the virt-launcher container can plant a symlink at the cache file path, causing virt-handler to follow it and overwrite an arbitrary host file with JSON content and change its ownership.

Published Jun 25, 2026 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: redhat

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.1% (30-day exploitation probability)+0
Technical severity (medium)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.14%

ahead of 3% of scored CVEs · Oct 15, 2026

Affects

Kubevirt

Kubevirt and 2 more

CVSS base

4.2

Medium · 2 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation

None

none · proof-of-concept · active

Automatable

can an attacker script the kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

Documented mitigation — access.redhat.com (NIST National Vulnerability Database)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Kubevirt Kubevirt, Red Hat Openshift Virtualization, Red Hat Red Hat OpenShift Virtualization 4).
Apply the documented mitigations until a definitive fix is available.
Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Kubevirt	Kubevirt	versions not specified by the source	Vulnerable	NIST National Vulnerability Database
Red Hat	Openshift Virtualization	≥ 4 and ≤ 4.22.0	Vulnerable	NIST National Vulnerability Database
Red Hat	Red Hat OpenShift Virtualization 4	versions not specified by the source	Vulnerable	CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Local

Attack complexity

High

Privileges required

Low

User interaction

None

Scope

Changed

Confidentiality

None

Integrity

Low

Availability

Low

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
4.2	CVSS 3.1	Medium	1.1	2.7	secalert@redhat.com via NIST National Vulnerability Database
4.2	CVSS 3.1	Medium	—	—	redhat via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:N/I:L/A:L (score shown at the top: secalert@redhat.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-61

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 15, 2026 · 3 reading(s) · max 0.14%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.

endpoint telemetry (EDR)

Timeline

What happened to this CVE, newest first.

2026
Affected products added · red hat/red hat openshift virtualization 4
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 13, 2026
Fix documented
Oct 13, 2026 · NIST National Vulnerability Database
CVSS changed · 4.2
Oct 13, 2026 · NIST National Vulnerability Database
Source status changed · → Analyzed
Oct 13, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 13, 2026 · NIST National Vulnerability Database
CVE published
Jun 25, 2026 · redhat

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

2 on the record

access.redhat.com/security/cve/CVE-2026-13218
Vendor Advisory, Mitigation, vdb-entry, x_refsource_REDHAT, NIST National Vulnerability Database
bugzilla.redhat.com/show_bug.cgi
Issue Tracking, Vendor Advisory, issue-tracking, x_refsource_REDHAT, NIST National Vulnerability Database

Elsewhere on this site

Kubevirt
every CVE for this vendor

CWE-61
other pages naming this weakness

Related CVEs (same products)

Medium CVE-2026-102623 Kubevirt: kubevirt: virt-controller nil-pointer dereference via malformed ephemeral volume 16d
Medium CVE-2026-79699 Podman: buildah: skopeo: containers/storage: malicious tar whiteout header allows replacement of extraction destination directory Sep 15, 2026
Medium CVE-2026-79705 Podman: buildah: buildah/copier: directory escape via crafted tar symlinks when used outside buildah by non-root callers Sep 15, 2026
High CVE-2026-17527 Virt-cdi-operator: containerized-data-importer: cdi.kubevirt.io:view aggregated clusterrole grants create on datavolumes/source, allowing unauthorized pvc clone Jul 27, 2026
Medium CVE-2026-13434 Virt-controller-rhel9: kubevirt: kubevirt: multus default-network annotation injection via unvalidated tenant networkname when externalnetresourceinjection is enabled Jun 26, 2026
Low CVE-2026-13322 Kubevirt: virt-handler-rhel9: kubevirt: unbounded virtio-serial readline in virt-handler causes oom denial of service Jun 25, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-13218 is "Kubevirt: kubevirt: symlink following in writetocachedfile allows host file overwrite from virt-launcher", rated Medium. It affects Kubevirt (Kubevirt); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 4.2 describes technical severity. EPSS 0.14% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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