{"api_version":"1","generated_at":"2026-08-17T16:01:07+00:00","cve":"CVE-2026-72471","urls":{"html":"https://cve.report/CVE-2026-72471","api":"https://cve.report/api/cve/CVE-2026-72471.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-72471","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-72471"},"summary":{"title":"fs/ntfs3: prevent potential lcn remains uninitialized","description":"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]","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-15 06:22:21","updated_at":"2026-08-17 06:19:15"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"7.1","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N","data":{"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"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"7.1","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N","data":{"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"}}],"references":[{"url":"https://git.kernel.org/stable/c/7ae7e98b71438c494532492cbf58fc0d7f7988bb","name":"https://git.kernel.org/stable/c/7ae7e98b71438c494532492cbf58fc0d7f7988bb","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/57ac2831c8e0f168090d38e3de758c6a59db44db","name":"https://git.kernel.org/stable/c/57ac2831c8e0f168090d38e3de758c6a59db44db","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-72471","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-72471","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c61326967728392931f8a2240cb2cf4c81b523c1 7ae7e98b71438c494532492cbf58fc0d7f7988bb git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c61326967728392931f8a2240cb2cf4c81b523c1 57ac2831c8e0f168090d38e3de758c6a59db44db git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 7.0","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.5 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"72471","cve":"CVE-2026-72471","epss":"0.001890000","percentile":"0.088740000","score_date":"2026-08-16","updated_at":"2026-08-17 00:01:05"},"legacy_qids":[]},"source_records":{"cve_program":{"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"},"nvd":{"publishedDate":"2026-08-15 06:22:21","lastModifiedDate":"2026-08-17 06:19:15","problem_types":[],"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}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"72471","Ordinal":"1","Title":"fs/ntfs3: prevent potential lcn remains uninitialized","CVE":"CVE-2026-72471","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"72471","Ordinal":"1","NoteData":"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]","Type":"Description","Title":"fs/ntfs3: prevent potential lcn remains uninitialized"}]}}}