CVE-2026-31591

Host crash via unlocked vCPU synchronization

Published Apr 24, 2026 · Updated Apr 24, 2026

Race condition in Linux Kernel KVM SEV-SNP 6.11 through 6.18.23, 6.19 through 6.19.13, and 7.0 allows local users to crash the host. The SNP launch-finish path synchronizes and encrypts every vCPU VMSA without holding each vCPU mutex, permitting concurrent userspace manipulation or execution. Access to a KVM SEV-SNP host and control of a vCPU during synchronization are required; exploitation corrupts vCPU state or crashes the host kernel.

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

Race condition in Linux Kernel KVM SEV-SNP 6.11 through 6.18.23, 6.19 through 6.19.13, and 7.0 allows local users to crash the host. The SNP launch-finish path synchronizes and encrypts every vCPU VMSA without holding each vCPU mutex, permitting concurrent userspace manipulation or execution. Access to a KVM SEV-SNP host and control of a vCPU during synchronization are required; exploitation corrupts vCPU state or crashes the host kernel.

The record

CVE
CVE-2026-31591
Published
Apr 24, 2026
Updated
Apr 24, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 24, 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=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <30fd9d8c82087742168db779929d8be0459b0716
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <4df77742e8b9a6b935bdf46f02fd0aca4d4ee7f5
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c87938fc7d99a06a7e5477c45b4e5a4148f85d66

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <30fd9d8c82087742168db779929d8be0459b0716; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <4df77742e8b9a6b935bdf46f02fd0aca4d4ee7f5; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c87938fc7d99a06a7e5477c45b4e5a4148f85d66

Published CVSS scores

5.5NVDCVSS: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

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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