Vulnerability-Lookup

CVE-2026-64561 (GCVE-0-2026-64561)

Vulnerability from cvelistv5 – Published: 2026-08-04 06:23 – Updated: 2026-08-04 06:23

Title

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

Summary

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

No CVSS data available.

Assigner

Linux

References

5 references

URL	Tags
https://git.kernel.org/stable/c/35e77467610c4a37c…
https://git.kernel.org/stable/c/0026dbb7de8ea76e9…
https://git.kernel.org/stable/c/f3477a6a4164f1528…
https://git.kernel.org/stable/c/bce0d3c26e2c761a4…
https://git.kernel.org/stable/c/2abd5287f08319fa3…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: f95eec9bed76d42194c23153cb1cc8f186bf91cb , < 35e77467610c4a37cb0ff54ee56b85f73b1f5700 (git) Affected: f95eec9bed76d42194c23153cb1cc8f186bf91cb , < 0026dbb7de8ea76e97d6edf42fc3cc084564e2bf (git) Affected: f95eec9bed76d42194c23153cb1cc8f186bf91cb , < f3477a6a4164f15287444eda685b5f6405dbd1e5 (git) Affected: f95eec9bed76d42194c23153cb1cc8f186bf91cb , < bce0d3c26e2c761a4bf43c8949f333fc7374eb2d (git) Affected: f95eec9bed76d42194c23153cb1cc8f186bf91cb , < 2abd5287f08319fa35764566b15c6e22cb1068db (git)
Linux	Linux	Affected: 5.9 Unaffected: 0 , < 5.9 (semver) Unaffected: 6.6.148 , ≤ 6.6.* (semver) Unaffected: 6.12.101 , ≤ 6.12.* (semver) Unaffected: 6.18.42 , ≤ 6.18.* (semver) Unaffected: 7.1.6 , ≤ 7.1.* (semver) Unaffected: 7.2-rc5 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

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        },
        {
          "url": "https://git.kernel.org/stable/c/2abd5287f08319fa35764566b15c6e22cb1068db"
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    "cveId": "CVE-2026-64561",
    "datePublished": "2026-08-04T06:23:21.094Z",
    "dateReserved": "2026-07-19T15:36:31.796Z",
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    "redhat_vex": {
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      "current_release_date": "2026-08-04T10:42:46+00:00",
      "cve": "CVE-2026-64561",
      "id": "CVE-2026-64561",
      "initial_release_date": "2026-08-04T00:00:00+00:00",
      "product_status:known_affected": "232",
      "product_status:known_not_affected": "42",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: KVM: x86: Check for invalid/obsolete root *after* making MMU pages available",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-64561.json",
      "version": "3"
    }
  }
}

GHSA-HP26-G45F-HXP5

Vulnerability from github – Published: 2026-08-04 09:31 – Updated: 2026-08-04 09:31

Details

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.

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-64561"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-04T07:16:30Z",
    "severity": null
  },
  "details": "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\u0027s role, any\nchildren created during the map/fetch will be created as invalid pages,\nthus violating KVM\u0027s 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\u0027t 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.",
  "id": "GHSA-hp26-g45f-hxp5",
  "modified": "2026-08-04T09:31:35Z",
  "published": "2026-08-04T09:31:35Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64561"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0026dbb7de8ea76e97d6edf42fc3cc084564e2bf"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2abd5287f08319fa35764566b15c6e22cb1068db"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/35e77467610c4a37cb0ff54ee56b85f73b1f5700"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bce0d3c26e2c761a4bf43c8949f333fc7374eb2d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f3477a6a4164f15287444eda685b5f6405dbd1e5"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.

Action not permitted

CVE-2026-64561 (GCVE-0-2026-64561)

GHSA-HP26-G45F-HXP5

Tags

Sightings

Nomenclature