---
id: CVE-2026-98718
title: 'KVM: SEV: Do cache maintenance on the source VM *before* clearing SEV state'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  KVM: SEV: Do cache maintenance on the source VM *before* clearing SEV state

  Explicitly flush caches after intra-host migration before clearing "SEV
  active" on the sour…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 37dfb676fafd1eef36fe0bb649607afbb0d5521b <
    8b7d4f68fef96cebe0b6dbb6e5607772337f7369
  - >-
    Linux >= d4cc2dff12116a700add601c0262132cc26e1b2c <
    de83ff6a4d8f3618473bedb3c4400020c22e8a8a
  - >-
    Linux >= 93de2a6a4b91b72607136dd656edf03fb399d27f <
    973ea70393e885e540f714904e51bc6cac80e3d7
  - Linux >= 6.18.55 < 6.18.56
  - Linux >= 7.2.9 < 7.2.10
  - Linux 7.3-rc5
published: '2026-10-18'
updated: '2026-10-18'
sourceUpdated: '2026-10-18T15:46:53.611Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-98718'
references:
  - url: 'https://git.kernel.org/stable/c/8b7d4f68fef96cebe0b6dbb6e5607772337f7369'
  - url: 'https://git.kernel.org/stable/c/de83ff6a4d8f3618473bedb3c4400020c22e8a8a'
  - url: 'https://git.kernel.org/stable/c/973ea70393e885e540f714904e51bc6cac80e3d7'
tags:
  - cve.org
ingestedAt: '2026-10-18T16:47:32.509Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

KVM: SEV: Do cache maintenance on the source VM *before* clearing SEV state

Explicitly flush caches after intra-host migration before clearing "SEV
active" on the source VM, as doing cache maintenance afterwards creates a
tiny window where memory reclaim could return memory to the host without
performing a cache flush, e.g. as pointed out by Sashiko:

  CPU1 in sev_migrate_from():
    src->active = false;

  CPU2 running concurrent unmap:
    Since active is false, the automatic cache flush in
    sev_guest_memory_reclaimed is skipped.
    The host frees and reallocates the page.

  CPU1 in sev_migrate_from():
    sev_writeback_caches(src_kvm);
    Executes a hardware cache flush (wbnoinvd), which writes the guest's old
    dirty ciphertext over the new page owner's data.

## Affected

- `Linux >= 37dfb676fafd1eef36fe0bb649607afbb0d5521b < 8b7d4f68fef96cebe0b6dbb6e5607772337f7369`
- `Linux >= d4cc2dff12116a700add601c0262132cc26e1b2c < de83ff6a4d8f3618473bedb3c4400020c22e8a8a`
- `Linux >= 93de2a6a4b91b72607136dd656edf03fb399d27f < 973ea70393e885e540f714904e51bc6cac80e3d7`
- `Linux >= 6.18.55 < 6.18.56`
- `Linux >= 7.2.9 < 7.2.10`
- `Linux 7.3-rc5`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.