CVE-2026-72191

Estado: RecibidaCrítica (9.8)—

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

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.

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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 declared size already extends past hdr1->used. This is the minimal fix; it preserves the existing hdr_find_split() contract and relies on the same out: cleanup path as the pre-existing error returns.

A prior OOB read in the very same indx_insert_into_buffer() memmove was fixed in commit b8c44949044e ("fs/ntfs3: Fix OOB read in indx_insert_into_buffer") by tightening hdr_find_e(), but that fix does not cover the split-point size field path addressed here: sp is returned by hdr_find_split(), not hdr_find_e(), and the underflow is driven by sp->size rather than hdr->used exceeding hdr->total.

Detalles técnicos trazas, registros y código del informe original

    used = used1 - to_copy - sp_size;
    memmove(de_t, Add2Ptr(sp, sp_size), used - le32_to_cpu(hdr1->de_off));

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Puntuación base: 9.8

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.70%
Percentil entre todas las CVEs puntuadas: 51
Fecha de la puntuación: 6/10/2026

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

ExplotaciónT1190 Exploit Public-Facing Applicationinitial access60 %

Inferido por reglas deterministas a partir del vector CVSS y la CWE. Solo orientativo.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Vulnerability Scanning Privileged Account Management Network Segmentation Limit Access to Resource Over Network Filter Network Traffic Application Isolation and Sandboxing

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Linux — Linux Kernel^AI

Referencias

JSON original (NVD)

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{
  "id": "CVE-2026-72191",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 9.8,
          "attackVector": "NETWORK",
          "baseSeverity": "CRITICAL",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "82cae269cfa953032fbb8980a7d554d60fb00b17",
              "lessThan": "8e4ba5a38c155bb3c1c11e63cd285b178cdb099e",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "82cae269cfa953032fbb8980a7d554d60fb00b17",
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              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "82cae269cfa953032fbb8980a7d554d60fb00b17",
              "lessThan": "b232eb5c9fe11ec2368e9b565db69c724c35fbd2",
              "versionType": "git"
            },
            {
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              "version": "82cae269cfa953032fbb8980a7d554d60fb00b17",
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            {
              "status": "affected",
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              "versionType": "git"
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            {
              "status": "affected",
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              "versionType": "git"
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            {
              "status": "affected",
              "version": "82cae269cfa953032fbb8980a7d554d60fb00b17",
              "lessThan": "f1df9d771df47aa40de6d70949c28720ae1e430d",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "fs/ntfs3/index.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.15"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "5.15",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "5.15.217",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "status": "unaffected",
              "version": "6.1.184",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.6.145",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.97",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver",
              "lessThanOrEqual": "7.1.*"
            },
            {
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "fs/ntfs3/index.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-08-15T06:21:37.537",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/1758a564b6ebe7f4a82f23c9851d1cae15549457",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/4c2f648139a0a86f4486170f72e24fedd4fae74e",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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    {
      "url": "https://git.kernel.org/stable/c/7bf74e6baf810fe325f111996496c678fc6e244f",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/8e4ba5a38c155bb3c1c11e63cd285b178cdb099e",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/b232eb5c9fe11ec2368e9b565db69c724c35fbd2",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/f1df9d771df47aa40de6d70949c28720ae1e430d",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/f3624cc069195001c88df7a291af215f2133ff2c",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nntfs3: validate split-point offset in indx_insert_into_buffer\n\nindx_insert_into_buffer() computes\n\n    used = used1 - to_copy - sp_size;\n    memmove(de_t, Add2Ptr(sp, sp_size), used - le32_to_cpu(hdr1->de_off));\n\nwhere sp and sp_size come from hdr_find_split().  hdr_find_split()\nwalks entries by le16_to_cpu(e->size) without validating that each\nstep stays within hdr->used or that the size field is at least\nsizeof(struct NTFS_DE).  index_hdr_check(), the on-load gatekeeper,\nonly validates header-level fields (used, total, de_off) and does\nnot walk per-entry sizes.\n\nA crafted NTFS image whose leaf INDEX_HDR reports used == total but\ncontains one interior NTFS_DE with size = 0xFFF0 therefore passes\nvalidation, descends to indx_insert_into_buffer() through the\nntfs_create() -> indx_insert_entry() path, and makes hdr_find_split()\nreturn an sp whose sp_size (0xFFF0) greatly exceeds the remaining\nbytes in the buffer.  The u32 subtraction underflows and the memmove\ncount becomes a near-4-GiB value, producing an out-of-bounds kernel\nwrite that corrupts adjacent allocations and panics the kernel.\n\nReproduced on 7.0.0-rc7 with UML + KASAN via a crafted image and a\nsingle 'touch' inside the mounted directory; crash site resolves to\nfs/ntfs3/index.c at the memmove.  Trigger requires only local mount\nof an attacker-supplied filesystem image (USB, loopback, or removable\nmedia auto-mount).\n\nReject the split whenever the chosen sp plus its declared size\nalready extends past hdr1->used.  This is the minimal fix; it\npreserves the existing hdr_find_split() contract and relies on the\nsame out: cleanup path as the pre-existing error returns.\n\nA prior OOB read in the very same indx_insert_into_buffer() memmove\nwas fixed in commit b8c44949044e (\"fs/ntfs3: Fix OOB read in\nindx_insert_into_buffer\") by tightening hdr_find_e(), but that fix\ndoes not cover the split-point size field path addressed here: sp is\nreturned by hdr_find_split(), not hdr_find_e(), and the underflow is\ndriven by sp->size rather than hdr->used exceeding hdr->total."
    }
  ],
  "lastModified": "2026-08-23T13:16:41.680",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}