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mm/khugepaged: invoke MMU notifiers in shmem/file collapse paths

Type: advisorySources: OSV

In the Linux kernel, the following vulnerability has been resolved: mm/khugepaged: invoke MMU notifiers in shmem/file collapse paths Any codepath that zaps page table entries must invoke MMU notifiers to ensure that secondary MMUs (like KVM) don't keep accessing pages which aren't mapped anymore. Secondary MMUs don't hold their own references to pages that are mirrored over, so failing to notify them can lead to page use-after-free. I'm marking this as addressing an issue introduced in commit f3f0e1d2150b ("khugepaged: add support of collapse for tmpfs/shmem pages"), but most of the security impact of this only came in commit 27e1f8273113 ("khugepaged: enable collapse pmd for pte-mapped THP"), which actually omitted flushes for the removal of present PTEs, not just for the removal of empty page tables.

Products
Kernel
Affected versions
Not specified
Fixed versions
4.14.303, 4.19.270, 4.9.337, 5.10.159, 5.15.83, 5.4.227, 6.0.13
CVEs
CVE-2022-48991
Confirmed fixed CVEs
Not specified
Updated in this feed
4 Nov 2026, 20:52 UTC · Revision 1

Source evidence

mm/khugepaged: invoke MMU notifiers in shmem/file collapse paths

core-osv · Original source

Published 21 Oct 2024, 20:06 UTC

In the Linux kernel, the following vulnerability has been resolved: mm/khugepaged: invoke MMU notifiers in shmem/file collapse paths Any codepath that zaps page table entries must invoke MMU notifiers to ensure that secondary MMUs (like KVM) don't keep accessing pages which aren't mapped anymore. Secondary MMUs don't hold their own references to pages that are mirrored over, so failing to notify them can lead to page use-after-free. I'm marking this as addressing an issue introduced in commit f3f0e1d2150b ("khugepaged: add support of collapse for tmpfs/shmem pages"), but most of the security impact of this only came in commit 27e1f8273113 ("khugepaged: enable collapse pmd for pte-mapped THP"), which actually omitted flushes for the removal of present PTEs, not just for the removal of empty page tables.

osv:CVE-2022-48991

Kernel

Fixed versions: 4.9.337, 4.14.303, 4.19.270, 5.4.227, 5.10.159, 5.15.83, 6.0.13

Complete source record
{
  "id": "9fabca41a043fefb3373d2cfff0d9e1692bd54b47e6fb3e90aa155f7c31e895b",
  "url": "https://osv.dev/vulnerability/CVE-2022-48991",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "mm/khugepaged: invoke MMU notifiers in shmem/file collapse paths",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: mm/khugepaged: invoke MMU notifiers in shmem/file collapse paths Any codepath that zaps page table entries must invoke MMU notifiers to ensure that secondary MMUs (like KVM) don't keep accessing pages which aren't mapped anymore. Secondary MMUs don't hold their own references to pages that are mirrored over, so failing to notify them can lead to page use-after-free. I'm marking this as addressing an issue introduced in commit f3f0e1d2150b (\"khugepaged: add support of collapse for tmpfs/shmem pages\"), but most of the security impact of this only came in commit 27e1f8273113 (\"khugepaged: enable collapse pmd for pte-mapped THP\"), which actually omitted flushes for the removal of present PTEs, not just for the removal of empty page tables.",
    "evidence": "osv:CVE-2022-48991",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "4.9.337",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "4.14.303",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "4.19.270",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.4.227",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.10.159",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.15.83",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.0.13",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2022-48991",
      "aliases": [
        "CVE-2022-48991"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "f3f0e1d2150b2b99da2cbdfaad000089efe9bf30"
                },
                {
                  "fixed": "275c626c131cfe141beeb6c575e31fa53d32da19"
                },
                {
                  "fixed": "c23105673228c349739e958fa33955ed8faddcaf"
                },
                {
                  "fixed": "ff2a1a6f869650aec99e9d070b5ab625bfbc5bc3"
                },
                {
                  "fixed": "5ffc2a75534d9d74d49760f983f8eb675fa63d69"
                },
                {
                  "fixed": "7f445ca2e0e59c7971d0b7b853465e50844ab596"
                },
                {
                  "fixed": "1a3f8c6cd29d9078cc81b29d39d0e9ae1d6a03c3"
                },
                {
                  "fixed": "5450535901d89a5dcca5fbbc59a24fe89caeb465"
                },
                {
                  "fixed": "f268f6cf875f3220afc77bdd0bf1bb136eb54db9"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2022-48991.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "4.8.0"
                },
                {
                  "fixed": "4.9.337"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "4.10.0"
                },
                {
                  "fixed": "4.14.303"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "4.15.0"
                },
                {
                  "fixed": "4.19.270"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "4.20.0"
                },
                {
                  "fixed": "5.4.227"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.5.0"
                },
                {
                  "fixed": "5.10.159"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.11.0"
                },
                {
                  "fixed": "5.15.83"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.16.0"
                },
                {
                  "fixed": "6.0.13"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2022-48991.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:39.843683563Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/1a3f8c6cd29d9078cc81b29d39d0e9ae1d6a03c3",
        "https://git.kernel.org/stable/c/275c626c131cfe141beeb6c575e31fa53d32da19",
        "https://git.kernel.org/stable/c/5450535901d89a5dcca5fbbc59a24fe89caeb465",
        "https://git.kernel.org/stable/c/5ffc2a75534d9d74d49760f983f8eb675fa63d69",
        "https://git.kernel.org/stable/c/7f445ca2e0e59c7971d0b7b853465e50844ab596",
        "https://git.kernel.org/stable/c/c23105673228c349739e958fa33955ed8faddcaf",
        "https://git.kernel.org/stable/c/f268f6cf875f3220afc77bdd0bf1bb136eb54db9",
        "https://git.kernel.org/stable/c/ff2a1a6f869650aec99e9d070b5ab625bfbc5bc3",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/48xxx/CVE-2022-48991.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2022-48991",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/48xxx/CVE-2022-48991.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2022-48991",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 506897,
  "published_at": "2024-10-21T20:06:08.312+00:00"
}