{
  "cveId": "CVE-2024-40950",
  "url": "https://patchblox.com/security/cve/CVE-2024-40950",
  "summary": "CVE-2024-40950 is fixed in linux on 1 platform, first by DEBIAN-CVE-2024-40950, released July 12, 2024. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "linux: In the Linux kernel, the following vulnerability has been resolved:  mm: huge_memory: fix misused mapping_large_folio...",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  mm: huge_memory: fix misused mapping_large_folio_support() for anon folios  When I did a large folios split test, a WARNING \u0022[ 5059.122759][ T166] Cannot split file folio to non-0 order\u0022 was triggered.  But the test cases are only for anonmous folios.  while mapping_large_folio_support() is only reasonable for page cache folios.  In split_huge_page_to_list_to_order(), the folio passed to mapping_large_folio_support() maybe anonmous folio.  The folio_test_anon() check is missing.  So the split of the anonmous THP is failed.  This is also the same for shmem_mapping().  We\u0027d better add a check for both.  But the shmem_mapping() in __split_huge_page() is not involved, as for anonmous folios, the end parameter is set to -1, so (head[i].index \u003E= end) is always false.  shmem_mapping() is not called.  Also add a VM_WARN_ON_ONCE() in mapping_large_folio_support() for anon mapping, So we can detect the wrong use more easily.  THP folios maybe exist in the pagecache even the file system doesn\u0027t support large folio, it is because when CONFIG_TRANSPARENT_HUGEPAGE is enabled, khugepaged will try to collapse read-only file-backed pages to THP.  But the mapping does not actually support multi order large folios properly.  Using /sys/kernel/debug/split_huge_pages to verify this, with this patch, large anon THP is successfully split and the warning is ceased.",
  "published": "2024-07-12T13:15:17Z",
  "severity": "medium",
  "cvss": 5.5,
  "cvssVector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
  "epss": 0.00208,
  "epssPercentile": 0.10969,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "6.9.7-1",
      "fix": "DEBIAN-CVE-2024-40950",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2024-40950",
      "released": "2024-07-12T13:15:17Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "6.9.7-1",
      "fix": "DEBIAN-CVE-2024-40950",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2024-40950",
      "released": "2024-07-12T13:15:17Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T00:53:09Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}