CVE-2026-31593

Host panic via encrypted VMSA state synchronization

Published Apr 24, 2026 · Updated Apr 24, 2026

Denial of service in Linux Kernel KVM allows local users to panic an SEV-SNP host by synchronizing an already-launched vCPU. sev_es_sync_vmsa writes vCPU state into a VMSA after SNP launch has encrypted that guest-private page, causing an RMP write fault. Reachability requires local KVM access on an AMD host with SNP enabled and an already-launched encrypted vCPU; the bounded consequence is a host-kernel panic.

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

Denial of service in Linux Kernel KVM allows local users to panic an SEV-SNP host by synchronizing an already-launched vCPU. sev_es_sync_vmsa writes vCPU state into a VMSA after SNP launch has encrypted that guest-private page, causing an RMP write fault. Reachability requires local KVM access on an AMD host with SNP enabled and an already-launched encrypted vCPU; the bounded consequence is a host-kernel panic.

The record

CVE
CVE-2026-31593
Published
Apr 24, 2026
Updated
Apr 24, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499.004
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 <692fdf05e55fa03960a1278afdc2478c12daea13
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <6ef109e01e1d35199e1a97ea68bdfd3cf3fbf9ab
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <8f85a4885eee8cb495961ffa371a91828afb9445
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c9609847ae65ca36233077c2b6cb2bc0fb37c77a

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <692fdf05e55fa03960a1278afdc2478c12daea13; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <6ef109e01e1d35199e1a97ea68bdfd3cf3fbf9ab; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <8f85a4885eee8cb495961ffa371a91828afb9445; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c9609847ae65ca36233077c2b6cb2bc0fb37c77a

Published CVSS scores

5.5NIST NVDCVSS: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

T1499.004Application or System Exploitation

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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