Vulnerability-Lookup

GHSA-W848-J2VG-QXFR

Vulnerability from github – Published: 2026-08-15 06:32 – Updated: 2026-08-17 06:33

Details

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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-72471"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-15T06:22:21Z",
    "severity": "HIGH"
  },
  "details": "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": "GHSA-w848-j2vg-qxfr",
  "modified": "2026-08-17T06:33:31Z",
  "published": "2026-08-15T06:32:25Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72471"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/57ac2831c8e0f168090d38e3de758c6a59db44db"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7ae7e98b71438c494532492cbf58fc0d7f7988bb"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}

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

Vulnerability from cvelistv5 – Published: 2026-08-15 05:57 – Updated: 2026-08-17 05:44

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

Linux mitre root

References

2 references

URL	Tags
https://git.kernel.org/stable/c/7ae7e98b71438c494…
https://git.kernel.org/stable/c/57ac2831c8e0f1680…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: c61326967728392931f8a2240cb2cf4c81b523c1 , < 7ae7e98b71438c494532492cbf58fc0d7f7988bb (git) Affected: c61326967728392931f8a2240cb2cf4c81b523c1 , < 57ac2831c8e0f168090d38e3de758c6a59db44db (git)
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"
}

Sightings

Author	Source	Type	Date	Other

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.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

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GHSA-W848-J2VG-QXFR

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

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