FKIE_CVE-2026-98718

Vulnerability from fkie_nvd - Published: 2026-10-18 16:17 - Updated: 2026-10-19 10:19
Severity
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 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.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/8b7d4f68fef96cebe0b6dbb6e5607772337f7369
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/973ea70393e885e540f714904e51bc6cac80e3d7
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/de83ff6a4d8f3618473bedb3c4400020c22e8a8a
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/x86/kvm/svm/sev.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "8b7d4f68fef96cebe0b6dbb6e5607772337f7369",
              "status": "affected",
              "version": "37dfb676fafd1eef36fe0bb649607afbb0d5521b",
              "versionType": "git"
            },
            {
              "lessThan": "de83ff6a4d8f3618473bedb3c4400020c22e8a8a",
              "status": "affected",
              "version": "d4cc2dff12116a700add601c0262132cc26e1b2c",
              "versionType": "git"
            },
            {
              "lessThan": "973ea70393e885e540f714904e51bc6cac80e3d7",
              "status": "affected",
              "version": "93de2a6a4b91b72607136dd656edf03fb399d27f",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/x86/kvm/svm/sev.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "6.18.56",
              "status": "affected",
              "version": "6.18.55",
              "versionType": "semver"
            },
            {
              "lessThan": "7.2.10",
              "status": "affected",
              "version": "7.2.9",
              "versionType": "semver"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: SEV: Do cache maintenance on the source VM *before* clearing SEV state\n\nExplicitly flush caches after intra-host migration before clearing \"SEV\nactive\" on the source VM, as doing cache maintenance afterwards creates a\ntiny window where memory reclaim could return memory to the host without\nperforming a cache flush, e.g. as pointed out by Sashiko:\n\n  CPU1 in sev_migrate_from():\n    src-\u003eactive = false;\n\n  CPU2 running concurrent unmap:\n    Since active is false, the automatic cache flush in\n    sev_guest_memory_reclaimed is skipped.\n    The host frees and reallocates the page.\n\n  CPU1 in sev_migrate_from():\n    sev_writeback_caches(src_kvm);\n    Executes a hardware cache flush (wbnoinvd), which writes the guest\u0027s old\n    dirty ciphertext over the new page owner\u0027s data."
    }
  ],
  "id": "CVE-2026-98718",
  "lastModified": "2026-10-19T10:19:36.047",
  "metrics": {},
  "published": "2026-10-18T16:17:25.363",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/8b7d4f68fef96cebe0b6dbb6e5607772337f7369"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/973ea70393e885e540f714904e51bc6cac80e3d7"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/de83ff6a4d8f3618473bedb3c4400020c22e8a8a"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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