What is the CVSS score of CVE-2026-27211?

CVE-2026-27211 has a CVSS 3.1 base score of 10.0 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N. EPSS exploitation probability: 0.0%.

Which versions of KVM are affected by CVE-2026-27211?

Cloud Hypervisor versions 34.0-50.0 contain a critical vulnerability allowing attackers to extract arbitrary files from host systems when using virtio-block storage devices.. A patch is available.

How to fix or mitigate CVE-2026-27211?

Within 24 hours: Inventory all Cloud Hypervisor deployments and identify instances running versions 34.0-50.0; assess whether virtio-block devices with raw image backing are in use. Within 7 days: Apply available vendor patches to all affected systems during maintenance windows, prioritizing production environments. Within 30 days: Validate patch deployment across infrastructure, conduct log review for exploitation attempts, and implement post-incident security controls.

KVM CVE-2026-27211

CRITICAL

External Control of File Name or Path (CWE-73)

2026-02-21 security-advisories@github.com

KVM Linux Information Disclosure Path Traversal Docker Kubernetes Cloud Hypervisor

10.0

CVSS 3.1 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

10.0 CRITICAL

AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

None

Lifecycle Timeline

Analysis Generated

Mar 12, 2026 - 22:04 vuln.today

Patch released

Feb 24, 2026 - 17:08 nvd

Patch available

CVE Published

Feb 21, 2026 - 06:17 nvd

CRITICAL 10.0

DescriptionGitHub Advisory

Cloud Hypervisor is a Virtual Machine Monitor for Cloud workloads. Versions 34.0 through 50.0 arevulnerable to arbitrary host file exfiltration (constrained by process privileges) when using virtio-block devices backed by raw images. A malicious guest can overwrite its disk header with a crafted QCOW2 structure pointing to a sensitive host path. Upon the next VM boot or disk scan, the image format auto-detection parses this header and serves the host file's contents to the guest. Guest-initiated VM reboots are sufficient to trigger a disk scan and do not cause the Cloud Hypervisor process to exit. Therefore, a single VM can perform this attack without needing interaction from the management stack. Successful exploitation requires the backing image to be either writable by the guest or sourced from an untrusted origin. Deployments utilizing only trusted, read-only images are not affected. This issue has been fixed in version 50.1. To workaround, enable land lock sandboxing and restrict process privileges and access.