CVE-2026-72471 (GCVE-0-2026-72471)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:57 – Updated: 2026-08-17 05:44
VLAI
Title
fs/ntfs3: prevent potential lcn remains uninitialized
Summary
In the Linux kernel, the following vulnerability has been resolved: fs/ntfs3: prevent potential lcn remains uninitialized The target VCN being sought was not found within runs[0], causing run_lookup() to return false. This causes run_lookup_entry() to return false, which in turn results in a len value of 0, and the new parameter passed to attr_data_get_block() is NULL. Collectively, these factors ultimately cause attr_data_get_block_locked() to exit prematurely without initializing lcn, thereby triggering [1]. To prevent [1], the clen check within ni_seek_data_or_hole() has been moved to occur before the lcn check. [1] BUG: KMSAN: uninit-value in ni_seek_data_or_hole+0x24f/0x5f0 fs/ntfs3/frecord.c:2862 ni_seek_data_or_hole+0x24f/0x5f0 fs/ntfs3/frecord.c:2862 ntfs_llseek+0x22a/0x4a0 fs/ntfs3/file.c:1530 vfs_llseek fs/read_write.c:391 [inline]
Severity
7.1 (High)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: c61326967728392931f8a2240cb2cf4c81b523c1 , < 7ae7e98b71438c494532492cbf58fc0d7f7988bb (git)
Affected: c61326967728392931f8a2240cb2cf4c81b523c1 , < 57ac2831c8e0f168090d38e3de758c6a59db44db (git)
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Linux Linux Affected: 7.0
Unaffected: 0 , < 7.0 (semver)
Unaffected: 7.1.5 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/ntfs3/frecord.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "7ae7e98b71438c494532492cbf58fc0d7f7988bb",
              "status": "affected",
              "version": "c61326967728392931f8a2240cb2cf4c81b523c1",
              "versionType": "git"
            },
            {
              "lessThan": "57ac2831c8e0f168090d38e3de758c6a59db44db",
              "status": "affected",
              "version": "c61326967728392931f8a2240cb2cf4c81b523c1",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/ntfs3/frecord.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "7.0"
            },
            {
              "lessThan": "7.0",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.5",
                  "versionStartIncluding": "7.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "7.0",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfs/ntfs3: prevent potential lcn remains uninitialized\n\nThe target VCN being sought was not found within runs[0], causing\nrun_lookup() to return false. This causes run_lookup_entry() to return\nfalse, which in turn results in a len value of 0, and the new parameter\npassed to attr_data_get_block() is NULL. Collectively, these factors\nultimately cause attr_data_get_block_locked() to exit prematurely without\ninitializing lcn, thereby triggering [1].\n\nTo prevent [1], the clen check within ni_seek_data_or_hole() has been\nmoved to occur before the lcn check.\n\n[1]\nBUG: KMSAN: uninit-value in ni_seek_data_or_hole+0x24f/0x5f0 fs/ntfs3/frecord.c:2862\n ni_seek_data_or_hole+0x24f/0x5f0 fs/ntfs3/frecord.c:2862\n ntfs_llseek+0x22a/0x4a0 fs/ntfs3/file.c:1530\n vfs_llseek fs/read_write.c:391 [inline]"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.1,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - On servers exporting an NTFS3-backed volume via ksmbd or nfsd, a remote client can trigger ntfs_llseek(SEEK_DATA/SEEK_HOLE) through FSCTL_QUERY_ALLOCATED_RANGES or NFS SEEK operations, exercising ni_seek_data_or_hole() without local shell access.\nAC:L - The bug is reliably reproducible with attacker-crafted NTFS metadata where the target VCN is absent from runs[0], causing attr_data_get_block_locked() to return success with clen=0 and leave lcn uninitialized; syzkaller demonstrated deterministic triggering.\nPR:L - Exploitation requires only an unprivileged local user with read access to a file on a mounted ntfs3 volume, or an authenticated SMB/NFS client with permission to open/query that file; mounting the filesystem itself is not required for the trigger path.\nUI:N - On typical server deployments the NTFS volume is already mounted and exported; the attacker only needs network or local file access to invoke lseek/SEEK_DATA/SEEK_HOLE on crafted metadata, with no additional victim interaction beyond normal file access.\nS:U - The flaw is confined to incorrect ntfs3 SEEK_DATA/SEEK_HOLE handling in kernel filesystem code and does not cross VM, container, or IOMMU security boundaries; impact remains within the same kernel security authority.\nC:H - ni_seek_data_or_hole() compares uninitialized stack variable lcn against RESIDENT_LCN/EOF_LCN/SPARSE_LCN before validating clen==0, constituting a kernel uninitialized-memory read whose branch outcomes and returned seek offsets can leak kernel stack residue to userspace or remote SMB/NFS clients.\nI:L - Garbage lcn values can force incorrect SEEK_DATA/SEEK_HOLE results (wrong offsets, premature -ENXIO, or invalid positions), corrupting the integrity of file-offset queries returned to local processes or remote clients even though no arbitrary kernel write primitive is demonstrated.\nA:N - The reported failure mode is a KMSAN uninit-value in ni_seek_data_or_hole(); production kernels without KMSAN take mis-branches that return errors or incorrect offsets rather than oopsing, panicking, or hanging the system."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:44:36.197Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/7ae7e98b71438c494532492cbf58fc0d7f7988bb"
        },
        {
          "url": "https://git.kernel.org/stable/c/57ac2831c8e0f168090d38e3de758c6a59db44db"
        }
      ],
      "title": "fs/ntfs3: prevent potential lcn remains uninitialized",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-72471",
    "datePublished": "2026-08-15T05:57:13.117Z",
    "dateReserved": "2026-08-09T03:40:39.934Z",
    "dateUpdated": "2026-08-17T05:44:36.197Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-72471",
      "date": "2026-08-27",
      "epss": "0.00315",
      "percentile": "0.23749"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-72471\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-08-15T06:22:21.213\",\"lastModified\":\"2026-08-17T06:19:15.027\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nfs/ntfs3: prevent potential lcn remains uninitialized\\n\\nThe target VCN being sought was not found within runs[0], causing\\nrun_lookup() to return false. This causes run_lookup_entry() to return\\nfalse, which in turn results in a len value of 0, and the new parameter\\npassed to attr_data_get_block() is NULL. Collectively, these factors\\nultimately cause attr_data_get_block_locked() to exit prematurely without\\ninitializing lcn, thereby triggering [1].\\n\\nTo prevent [1], the clen check within ni_seek_data_or_hole() has been\\nmoved to occur before the lcn check.\\n\\n[1]\\nBUG: KMSAN: uninit-value in ni_seek_data_or_hole+0x24f/0x5f0 fs/ntfs3/frecord.c:2862\\n ni_seek_data_or_hole+0x24f/0x5f0 fs/ntfs3/frecord.c:2862\\n ntfs_llseek+0x22a/0x4a0 fs/ntfs3/file.c:1530\\n vfs_llseek fs/read_write.c:391 [inline]\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"fs/ntfs3/frecord.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"c61326967728392931f8a2240cb2cf4c81b523c1\",\"lessThan\":\"7ae7e98b71438c494532492cbf58fc0d7f7988bb\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"c61326967728392931f8a2240cb2cf4c81b523c1\",\"lessThan\":\"57ac2831c8e0f168090d38e3de758c6a59db44db\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"fs/ntfs3/frecord.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"7.0\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"7.0\",\"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:L/UI:N/S:U/C:H/I:L/A:N\",\"baseScore\":7.1,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"LOW\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":2.8,\"impactScore\":4.2}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/57ac2831c8e0f168090d38e3de758c6a59db44db\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/7ae7e98b71438c494532492cbf58fc0d7f7988bb\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-18T16:29:38+00:00",
      "cve": "CVE-2026-72471",
      "id": "CVE-2026-72471",
      "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: fs/ntfs3: prevent potential lcn remains uninitialized",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-72471.json",
      "version": "3"
    }
  }
}



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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.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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