CVE-2026-64309

Host crash via unnecessary SNP initialization

Published Jul 25, 2026 · Updated Jul 25, 2026

Denial of service in affected Linux Kernel builds allows local users to crash a KVM host through /dev/sev ioctls. The SNP_COMMIT ioctl path unnecessarily initializes SNP firmware and, after failed SEV initialization, can clear the global MSR_VM_HSAVE_PA used by active virtual machines. Exploitation requires low-privileged local device access, failed SEV initialization, and active KVM guests; a subsequent VMRUN can fault and crash the host.

CVSS severity5.5
Medium
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in affected Linux Kernel builds allows local users to crash a KVM host through /dev/sev ioctls. The SNP_COMMIT ioctl path unnecessarily initializes SNP firmware and, after failed SEV initialization, can clear the global MSR_VM_HSAVE_PA used by active virtual machines. Exploitation requires low-privileged local device access, failed SEV initialization, and active KVM guests; a subsequent VMRUN can fault and crash the host.

The record

CVE
CVE-2026-64309
Published
Jul 25, 2026
Updated
Jul 25, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-908, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 25, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=1c3506ea8599a3ad1b9aae5cbd573134f8d18db7 <74768f73854d647a6462f252dc8782ab8a835211
  2. Affected versionversion=6.12.75 <6.12.96
  3. Affected versionversion=6.16
  4. Affected versionversion=ceac7fb89e8da465aec3ac3c20477f912f5c3a6c <5a1364da2f04217a36e2fdfa2db4ee025b383a20
  5. Affected versionversion=ceac7fb89e8da465aec3ac3c20477f912f5c3a6c <67ed191b4c8bdf432a3f32d1eb302880b4795cd1
  6. Affected versionversion=ceac7fb89e8da465aec3ac3c20477f912f5c3a6c <7a361c74bb12f3398c388905f1d325be642cd36e

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1c3506ea8599a3ad1b9aae5cbd573134f8d18db7 <74768f73854d647a6462f252dc8782ab8a835211; version=6.12.75 <6.12.96; version=6.16; version=ceac7fb89e8da465aec3ac3c20477f912f5c3a6c <5a1364da2f04217a36e2fdfa2db4ee025b383a20; version=ceac7fb89e8da465aec3ac3c20477f912f5c3a6c <67ed191b4c8bdf432a3f32d1eb302880b4795cd1; version=ceac7fb89e8da465aec3ac3c20477f912f5c3a6c <7a361c74bb12f3398c388905f1d325be642cd36e

Published CVSS scores

5.5Red HatCVSS: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.

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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

CWE-908Use of Uninitialized Resource
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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