CVE-2026-89612 (GCVE-0-2026-89612)
Vulnerability from cvelistv5
Published
2026-09-11 19:45
Modified
2026-10-19 08:49
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
ntfs: reject invalid MFT LCNs from boot sector
The NTFS boot sector stores the MFT and MFTMirr locations as unsigned
64-bit LCNs, but parse_ntfs_boot_sector() decoded them into an s64.
A crafted high-bit value could therefore become negative and pass
the existing upper-bound check. The invalid value then propagated into
the MFT zone allocator and could result in an out-of-bounds access to
lcn_empty_bits_per_page.
References
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"fs/ntfs/super.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "8f8420b68a6f05ca2b03779d8208814ec539b9e5",
"status": "affected",
"version": "11ccc9107dc460de28af90fac1f42404d9802735",
"versionType": "git"
},
{
"lessThan": "cc9d09fef78410bcd37ac05168cbd5f6dd75d3d2",
"status": "affected",
"version": "11ccc9107dc460de28af90fac1f42404d9802735",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"fs/ntfs/super.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "7.1"
},
{
"lessThan": "7.1",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.2.*",
"status": "unaffected",
"version": "7.2.4",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2.4",
"versionStartIncluding": "7.1",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.3",
"versionStartIncluding": "7.1",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nntfs: reject invalid MFT LCNs from boot sector\n\nThe NTFS boot sector stores the MFT and MFTMirr locations as unsigned\n64-bit LCNs, but parse_ntfs_boot_sector() decoded them into an s64.\n\nA crafted high-bit value could therefore become negative and pass\nthe existing upper-bound check. The invalid value then propagated into\nthe MFT zone allocator and could result in an out-of-bounds access to\nlcn_empty_bits_per_page."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 9.8,
"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"
},
"scenarios": [
{
"lang": "en",
"value": "AV:N - After a crafted NTFS volume is mounted, fs/ntfs registers ntfs_export_ops, so nfsd/ksmbd VFS writes and creates reach ntfs_cluster_alloc() and index the poisoned MFT-zone LCN into lcn_empty_bits_per_page without local shell access.\nAC:L - The attacker fully controls the unsigned 64-bit MFT/MFTMirr LCNs in the boot sector; a high-bit value becomes a negative s64, bypasses the signed upper-bound check, and later allocator walks use that value as bmp_pos with no race or rare config.\nPR:N - Triggering the allocator needs only write access to a mounted NTFS export (guest/anonymous SMB or a permissive NFS export) or an unprivileged write on an already-mounted volume, not init-namespace root or CAP_SYS_ADMIN at trigger time.\nUI:N - After the crafted volume is mounted and exported, ordinary remote or local write/create operations invoke ntfs_cluster_alloc() with the poisoned mft_zone_pos; no extra victim mount dialog or USB insertion is required during the attack.\nS:U - Out-of-bounds access to vol-\u003elcn_empty_bits_per_page corrupts kernel heap within the host OS security domain and does not cross a VM, container, or IOMMU boundary to another authority.\nC:H - ntfs_cluster_alloc() reads lcn_empty_bits_per_page[index] where index is derived from the attacker-chosen negative LCN (truncating to a controllable pgoff_t on 32-bit), an unbounded kernel heap out-of-bounds read that can disclose adjacent objects.\nI:H - The same attacker-influenced index is passed to ntfs_set_lcn_empty_bits(), which increments or decrements lcn_empty_bits_per_page[index], a kernel heap out-of-bounds write exploitable for arbitrary write and control-flow hijacking.\nA:H - The out-of-bounds lcn_empty_bits_per_page index causes a kernel oops or KASAN slab-out-of-bounds fault in ntfs_cluster_alloc()/ntfs_set_lcn_empty_bits(), crashing or hanging the host even when not fully exploited."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-10-19T08:49:44.526Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/8f8420b68a6f05ca2b03779d8208814ec539b9e5"
},
{
"url": "https://git.kernel.org/stable/c/cc9d09fef78410bcd37ac05168cbd5f6dd75d3d2"
}
],
"title": "ntfs: reject invalid MFT LCNs from boot sector",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-89612",
"datePublished": "2026-09-11T19:45:13.415Z",
"dateReserved": "2026-09-11T19:38:34.734Z",
"dateUpdated": "2026-10-19T08:49:44.526Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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