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": "2026-09-22",
      "epss": "0.00315",
      "percentile": "0.24634"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "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"
                  }
                ]
              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "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]"
          }
        ],
        "id": "CVE-2026-72471",
        "lastModified": "2026-08-17T06:19:15.027",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "NONE",
                "baseScore": 7.1,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "LOW",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N",
                "version": "3.1"
              },
              "exploitabilityScore": 2.8,
              "impactScore": 4.2,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
            }
          ]
        },
        "published": "2026-08-15T06:22:21.213",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/57ac2831c8e0f168090d38e3de758c6a59db44db"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/7ae7e98b71438c494532492cbf58fc0d7f7988bb"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    },
    "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"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-08-27T16:52:15Z",
      "cve": "CVE-2026-72471",
      "id": "CVE-2026-72471",
      "initial_release_date": "2026-08-27T16:52:15Z",
      "product_status:known_not_affected": "290",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-72471",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-72471.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.

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.
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  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
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  • 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.



Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.