ntfs3: validate split-point offset in indx_insert_into_buffer

{
  "id": "a874090a373dcae2f608b415a7ca52668eae5a07f131f569d7942288db635c62",
  "url": "https://osv.dev/vulnerability/CVE-2026-72191",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ntfs3: validate split-point offset in indx_insert_into_buffer",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: ntfs3: validate split-point offset in indx_insert_into_buffer indx_insert_into_buffer() computes used = used1 - to_copy - sp_size; memmove(de_t, Add2Ptr(sp, sp_size), used - le32_to_cpu(hdr1->de_off)); where sp and sp_size come from hdr_find_split(). hdr_find_split() walks entries by le16_to_cpu(e->size) without validating that each step stays within hdr->used or that the size field is at least sizeof(struct NTFS_DE). index_hdr_check(), the on-load gatekeeper, only validates header-level fields (used, total, de_off) and does not walk per-entry sizes. A crafted NTFS image whose leaf INDEX_HDR reports used == total but contains one interior NTFS_DE with size = 0xFFF0 therefore passes validation, descends to indx_insert_into_buffer() through the ntfs_create() -> indx_insert_entry() path, and makes hdr_find_split() return an sp whose sp_size (0xFFF0) greatly exceeds the remaining bytes in the buffer. The u32 subtraction underflows and the memmove count becomes a near-4-GiB value, producing an out-of-bounds kernel write that corrupts adjacent allocations and panics the kernel. Reproduced on 7.0.0-rc7 with UML + KASAN via a crafted image and a single 'touch' inside the mounted directory; crash site resolves to fs/ntfs3/index.c at the memmove. Trigger requires only local mount of an attacker-supplied filesystem image (USB, loopback, or removable media auto-mount). Reject the split whenever the chosen sp plus its dec",
    "evidence": "osv:CVE-2026-72191",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.15.217",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.184",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.145",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.97",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.40",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.1.5",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "critical",
    "structured": {
      "id": "CVE-2026-72191",
      "aliases": [
        "CVE-2026-72191"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
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                  "introduced": "82cae269cfa953032fbb8980a7d554d60fb00b17"
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                {
                  "fixed": "8e4ba5a38c155bb3c1c11e63cd285b178cdb099e"
                },
                {
                  "fixed": "4c2f648139a0a86f4486170f72e24fedd4fae74e"
                },
                {
                  "fixed": "b232eb5c9fe11ec2368e9b565db69c724c35fbd2"
                },
                {
                  "fixed": "7bf74e6baf810fe325f111996496c678fc6e244f"
                },
                {
                  "fixed": "f3624cc069195001c88df7a291af215f2133ff2c"
                },
                {
                  "fixed": "1758a564b6ebe7f4a82f23c9851d1cae15549457"
                },
                {
                  "fixed": "f1df9d771df47aa40de6d70949c28720ae1e430d"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-72191.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.15.0"
                },
                {
                  "fixed": "5.15.217"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.16.0"
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                {
                  "fixed": "6.1.184"
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            {
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                  "introduced": "6.2.0"
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                {
                  "fixed": "6.6.145"
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            {
              "type": "ECOSYSTEM",
              "events": [
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                  "introduced": "6.7.0"
                },
                {
                  "fixed": "6.12.97"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.18.40"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "7.1.5"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-72191.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:29.424851222Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/1758a564b6ebe7f4a82f23c9851d1cae15549457",
        "https://git.kernel.org/stable/c/4c2f648139a0a86f4486170f72e24fedd4fae74e",
        "https://git.kernel.org/stable/c/7bf74e6baf810fe325f111996496c678fc6e244f",
        "https://git.kernel.org/stable/c/8e4ba5a38c155bb3c1c11e63cd285b178cdb099e",
        "https://git.kernel.org/stable/c/b232eb5c9fe11ec2368e9b565db69c724c35fbd2",
        "https://git.kernel.org/stable/c/f1df9d771df47aa40de6d70949c28720ae1e430d",
        "https://git.kernel.org/stable/c/f3624cc069195001c88df7a291af215f2133ff2c",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72191.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-72191",
        "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/2026/72xxx/CVE-2026-72191.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-72191",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 496383,
  "published_at": "2026-08-15T05:53:51.893+00:00"
}