CVE-2026-64561

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Check for invalid/obsolete root *after* making MMU pages available Check for a "stale" page fault, i.e. for an invalid and/or obsolete root, after making MMU pages available for the shadow MMU. If reclaiming shadow pages zaps an in-use root, i.e. marks it invalid, then KVM will attempt to map memory into an invalid root. On its own, populating an invalid root is "fine", but because child shadow pages inherit their parent's role, any children created during the map/fetch will be created as invalid pages, thus violating KVM's invariant that invalid pages are never on the list of active MMU pages. Note, the underlying flaw has existed since KVM first started tracking invalid roots in 2008 (commit 2e53d63acba7, "KVM: MMU: ignore zapped root pagetables"), but the true badness only came along in 2020 (Linux 5.9) with the invariant that invalid shadow pages can't be on the list of active pages. Note #2, inheriting role.invalid when creating child shadow pages is also far from ideal; that flaw will be addressed separately.

Severity

HIGH

CVSS score

8.8 (v3.1)

Vulnerability status

Received

Source identifier

416baaa9-dc9f-4396-8d5f-8c081fb06d67

Published

2026-08-04 07:16:30.937000

Last modified

2026-10-19 21:17:46.580000

View original CVE JSON

{
  "id": "CVE-2026-64561",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-08-04T07:16:30.937",
  "lastModified": "2026-10-19T21:17:46.580",
  "vulnStatus": "Received",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: x86: Check for invalid/obsolete root *after* making MMU pages available\n\nCheck for a \"stale\" page fault, i.e. for an invalid and/or obsolete root,\nafter making MMU pages available for the shadow MMU.  If reclaiming shadow\npages zaps an in-use root, i.e. marks it invalid, then KVM will attempt to\nmap memory into an invalid root.  On its own, populating an invalid root is\n\"fine\", but because child shadow pages inherit their parent's role, any\nchildren created during the map/fetch will be created as invalid pages,\nthus violating KVM's invariant that invalid pages are never on the list of\nactive MMU pages.\n\nNote, the underlying flaw has existed since KVM first started tracking\ninvalid roots in 2008 (commit 2e53d63acba7, \"KVM: MMU: ignore zapped root\npagetables\"), but the true badness only came along in 2020 (Linux 5.9)\nwith the invariant that invalid shadow pages can't be on the list of\nactive pages.\n\nNote #2, inheriting role.invalid when creating child shadow pages is also\nfar from ideal; that flaw will be addressed separately."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "arch/x86/kvm/mmu/mmu.c",
            "arch/x86/kvm/mmu/paging_tmpl.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "f95eec9bed76d42194c23153cb1cc8f186bf91cb",
              "lessThan": "62ef67af1878fa2cd066642f2f59e33ade95f637",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "f95eec9bed76d42194c23153cb1cc8f186bf91cb",
              "lessThan": "65c4f7a1028cf01a93a2762d679c289810ede990",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "f95eec9bed76d42194c23153cb1cc8f186bf91cb",
              "lessThan": "35e77467610c4a37cb0ff54ee56b85f73b1f5700",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "f95eec9bed76d42194c23153cb1cc8f186bf91cb",
              "lessThan": "0026dbb7de8ea76e97d6edf42fc3cc084564e2bf",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "f95eec9bed76d42194c23153cb1cc8f186bf91cb",
              "lessThan": "f3477a6a4164f15287444eda685b5f6405dbd1e5",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "f95eec9bed76d42194c23153cb1cc8f186bf91cb",
              "lessThan": "bce0d3c26e2c761a4bf43c8949f333fc7374eb2d",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "f95eec9bed76d42194c23153cb1cc8f186bf91cb",
              "lessThan": "2abd5287f08319fa35764566b15c6e22cb1068db",
              "versionType": "git",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "arch/x86/kvm/mmu/mmu.c",
            "arch/x86/kvm/mmu/paging_tmpl.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "5.9",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "5.9",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "5.15.218",
              "lessThanOrEqual": "5.15.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.1.183",
              "lessThanOrEqual": "6.1.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.6.148",
              "lessThanOrEqual": "6.6.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.12.101",
              "lessThanOrEqual": "6.12.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.18.42",
              "lessThanOrEqual": "6.18.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.1.6",
              "lessThanOrEqual": "7.1.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.2",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
          "baseScore": 8.8,
          "baseSeverity": "HIGH",
          "attackVector": "LOCAL",
          "attackComplexity": "LOW",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "CHANGED",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 2.0,
        "impactScore": 6.0
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-10-16T15:42:48.794184Z",
          "id": "CVE-2026-64561",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-362"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/0026dbb7de8ea76e97d6edf42fc3cc084564e2bf",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/2abd5287f08319fa35764566b15c6e22cb1068db",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
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      "url": "https://git.kernel.org/stable/c/35e77467610c4a37cb0ff54ee56b85f73b1f5700",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/62ef67af1878fa2cd066642f2f59e33ade95f637",
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    {
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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    {
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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    {
      "url": "https://github.com/V4bel/Zapscape",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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}