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KVM: x86: Check for invalid/obsolete root *after* making MMU pages available

Type: advisorySource: Official CVE List1 source record

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.

Announced Source revision 1
Original source ↗

CVE-2026-64561

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-64561

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "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"
      }
    ],
    "programFiles": [
      "arch/x86/kvm/mmu/mmu.c",
      "arch/x86/kvm/mmu/paging_tmpl.h"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "5.9"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "5.9",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.15.218",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.183",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.148",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.101",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.42",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.1.6",
        "versionType": "semver",
        "lessThanOrEqual": "7.1.*"
      },
      {
        "status": "unaffected",
        "version": "7.2",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "arch/x86/kvm/mmu/mmu.c",
      "arch/x86/kvm/mmu/paging_tmpl.h"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-64561

Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event
#41088 · Revision 1
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Publisher date
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