CVE-2026-72191 (GCVE-0-2026-72191)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:53 – Updated: 2026-08-17 05:41
VLAI
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 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.
Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 82cae269cfa953032fbb8980a7d554d60fb00b17 , < b232eb5c9fe11ec2368e9b565db69c724c35fbd2 (git)
Affected: 82cae269cfa953032fbb8980a7d554d60fb00b17 , < 7bf74e6baf810fe325f111996496c678fc6e244f (git)
Affected: 82cae269cfa953032fbb8980a7d554d60fb00b17 , < f3624cc069195001c88df7a291af215f2133ff2c (git)
Affected: 82cae269cfa953032fbb8980a7d554d60fb00b17 , < 1758a564b6ebe7f4a82f23c9851d1cae15549457 (git)
Affected: 82cae269cfa953032fbb8980a7d554d60fb00b17 , < f1df9d771df47aa40de6d70949c28720ae1e430d (git)
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Linux Linux Affected: 5.15
Unaffected: 0 , < 5.15 (semver)
Unaffected: 6.6.145 , ≤ 6.6.* (semver)
Unaffected: 6.12.97 , ≤ 6.12.* (semver)
Unaffected: 6.18.40 , ≤ 6.18.* (semver)
Unaffected: 7.1.5 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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{
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      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/ntfs3/index.c"
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      "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-\u003ede_off));\n\nwhere sp and sp_size come from hdr_find_split().  hdr_find_split()\nwalks entries by le16_to_cpu(e-\u003esize) without validating that each\nstep stays within hdr-\u003eused 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() -\u003e 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 \u0027touch\u0027 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-\u003eused.  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-\u003esize rather than hdr-\u003eused exceeding hdr-\u003etotal."
        }
      ],
      "metrics": [
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            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
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              "value": "AV:N - Remote SMB CREATE via ksmbd vfs_create on an ntfs3-exported share reaches ntfs_create_inode\u2192indx_insert_entry\u2192indx_insert_into_buffer; the same memmove path is also reachable locally via open(O_CREAT)/touch on a mounted crafted image.\nAC:L - The attacker fully controls the on-disk leaf INDEX_HDR and NTFS_DE size (e.g. 0xFFF0); once the buffer is full and a create forces a split, hdr_find_split() deterministically selects the bad entry and the u32 underflow yields a reliable near-4GiB OOB memmove with no race.\nPR:N - Exploitation requires only a crafted NTFS image and a create in the malicious directory\u2014no root on the target\u2014via udisks2/systemd automount of attacker USB media, or a remote ksmbd client with guest/anonymous write access to an already-mounted ntfs3 export.\nUI:N - After the crafted volume is mounted (automounter or admin), a single attacker-initiated touch/create or remote SMB CREATE in the prepared full directory triggers the split and OOB memmove without any further victim clicks, prompts, or confirmation.\nS:U - The OOB memmove corrupts kernel heap memory within the same host OS security domain as ntfs3; it can enable local privilege escalation but does not cross a VM/hypervisor, IOMMU, or container sandbox boundary.\nC:H - The underflowed memmove length reads far beyond the kmalloc\u0027d index buffer from attacker-controlled on-disk bytes, giving a large out-of-bounds kernel heap read and disclosure/corruption primitive in addition to the write side.\nI:H - The same memmove performs a massive out-of-bounds kernel heap write of adjacent slab objects with attacker-influenced source data, enabling arbitrary memory corruption and potential control-flow hijack beyond a simple denial of service.\nA:H - Reproduced on 7.0.0-rc7 with KASAN: the oversized memmove corrupts adjacent allocations and panics the kernel at fs/ntfs3/index.c; even failed exploitation attempts typically cause oops or hard lockup from the unbounded copy."
            }
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        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:41:18.532Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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          "url": "https://git.kernel.org/stable/c/b232eb5c9fe11ec2368e9b565db69c724c35fbd2"
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          "url": "https://git.kernel.org/stable/c/7bf74e6baf810fe325f111996496c678fc6e244f"
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        },
        {
          "url": "https://git.kernel.org/stable/c/f1df9d771df47aa40de6d70949c28720ae1e430d"
        }
      ],
      "title": "ntfs3: validate split-point offset in indx_insert_into_buffer",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-72191",
    "datePublished": "2026-08-15T05:53:51.893Z",
    "dateReserved": "2026-08-09T03:40:39.911Z",
    "dateUpdated": "2026-08-17T05:41:18.532Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
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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 \u0027touch\u0027 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-\u003eused.  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-\u003esize rather than hdr-\u003eused exceeding hdr-\u003etotal.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"fs/ntfs3/index.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"82cae269cfa953032fbb8980a7d554d60fb00b17\",\"lessThan\":\"b232eb5c9fe11ec2368e9b565db69c724c35fbd2\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"82cae269cfa953032fbb8980a7d554d60fb00b17\",\"lessThan\":\"7bf74e6baf810fe325f111996496c678fc6e244f\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"82cae269cfa953032fbb8980a7d554d60fb00b17\",\"lessThan\":\"f3624cc069195001c88df7a291af215f2133ff2c\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"82cae269cfa953032fbb8980a7d554d60fb00b17\",\"lessThan\":\"1758a564b6ebe7f4a82f23c9851d1cae15549457\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"82cae269cfa953032fbb8980a7d554d60fb00b17\",\"lessThan\":\"f1df9d771df47aa40de6d70949c28720ae1e430d\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"fs/ntfs3/index.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"5.15\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"5.15\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.6.145\",\"lessThanOrEqual\":\"6.6.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.97\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.40\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.5\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":9.8,\"baseSeverity\":\"CRITICAL\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":5.9}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/1758a564b6ebe7f4a82f23c9851d1cae15549457\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/7bf74e6baf810fe325f111996496c678fc6e244f\",\"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\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-18T15:16:03+00:00",
      "cve": "CVE-2026-72191",
      "id": "CVE-2026-72191",
      "initial_release_date": "2026-08-15T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: ntfs3: validate split-point offset in indx_insert_into_buffer",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-72191.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-08-21T00:42:47Z",
      "cve": "CVE-2026-72191",
      "id": "CVE-2026-72191",
      "initial_release_date": "2026-08-21T00:42:47Z",
      "product_status:known_affected": "129",
      "product_status:known_not_affected": "155",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-72191",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-72191.json",
      "version": "2"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
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