CVE-2026-46071

Host service interruption via vmcb12 dirty-bit clearing

Published May 27, 2026 · Updated May 27, 2026

An nSVM flaw in affected Linux Kernel releases allows local users to interrupt service through nested virtualization on AMD hosts. During nested_svm_vmexit(), svm_copy_lbrs() clears the VMCB_LBR clean bit in vmcb12 even though that operation is architecturally undefined. The path requires low-privilege local KVM access and nested SVM execution on an AMD host; the reported consequence is limited to availability.

CVSS severity5.5
Medium
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

An nSVM flaw in affected Linux Kernel releases allows local users to interrupt service through nested virtualization on AMD hosts. During nested_svm_vmexit(), svm_copy_lbrs() clears the VMCB_LBR clean bit in vmcb12 even though that operation is architecturally undefined. The path requires low-privilege local KVM access and nested SVM execution on an AMD host; the reported consequence is limited to availability.

The record

CVE
CVE-2026-46071
Published
May 27, 2026
Updated
May 27, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 27, 2026CVE publishedPublication date reported by the CVE source.
  2. May 27, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.19
  2. Affected versionversion=d20c796ca3709801f8a7fa36e8770a3dd8ebd34e <9efe23568806d1cd06f7d146f9b3037b8d585a9f
  3. Affected versionversion=d20c796ca3709801f8a7fa36e8770a3dd8ebd34e <a3f0981a5a0e0bd51ad74cc7d9eed32294b24002
  4. Affected versionversion=d20c796ca3709801f8a7fa36e8770a3dd8ebd34e <b53ab5167a81537777ac780bbd93d32613aa3bda

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=5.19; version=d20c796ca3709801f8a7fa36e8770a3dd8ebd34e <9efe23568806d1cd06f7d146f9b3037b8d585a9f; version=d20c796ca3709801f8a7fa36e8770a3dd8ebd34e <a3f0981a5a0e0bd51ad74cc7d9eed32294b24002; version=d20c796ca3709801f8a7fa36e8770a3dd8ebd34e <b53ab5167a81537777ac780bbd93d32613aa3bda

Published CVSS scores

5.5NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5Canonical UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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