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CVE-2026-89612 (GCVE-0-2026-89612)

Vulnerability from cvelistv5 – Published: 2026-09-11 19:45 – Updated: 2026-09-13 06:31
VLAI
Title
ntfs: reject invalid MFT LCNs from boot sector
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.
Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 11ccc9107dc460de28af90fac1f42404d9802735 , < 8f8420b68a6f05ca2b03779d8208814ec539b9e5 (git)
Affected: 11ccc9107dc460de28af90fac1f42404d9802735 , < cc9d09fef78410bcd37ac05168cbd5f6dd75d3d2 (git)
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Linux Linux Affected: 7.1
Unaffected: 0 , < 7.1 (semver)
Unaffected: 7.2.4 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)
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{
  "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": [
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              "status": "affected",
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              "versionType": "git"
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              "status": "affected",
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          "vendor": "Linux",
          "versions": [
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              "version": "7.1"
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              "version": "0",
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              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver"
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            {
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              "status": "unaffected",
              "version": "7.3-rc1",
              "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-rc1",
                  "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": "2026-09-13T06:31:50.050Z",
        "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": "2026-09-13T06:31:50.050Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-89612",
      "date": "2026-09-16",
      "epss": "0.00553",
      "percentile": "0.44805"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-89612\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-09-11T20:19:46.313\",\"lastModified\":\"2026-09-13T07:17:26.730\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"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.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"fs/ntfs/super.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"11ccc9107dc460de28af90fac1f42404d9802735\",\"lessThan\":\"8f8420b68a6f05ca2b03779d8208814ec539b9e5\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"11ccc9107dc460de28af90fac1f42404d9802735\",\"lessThan\":\"cc9d09fef78410bcd37ac05168cbd5f6dd75d3d2\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"fs/ntfs/super.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"7.1\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"7.1\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2.4\",\"lessThanOrEqual\":\"7.2.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.3-rc1\",\"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:N/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":9.8,\"baseSeverity\":\"CRITICAL\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":5.9}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/8f8420b68a6f05ca2b03779d8208814ec539b9e5\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/cc9d09fef78410bcd37ac05168cbd5f6dd75d3d2\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-09-13T06:59:12+00:00",
      "cve": "CVE-2026-89612",
      "id": "CVE-2026-89612",
      "initial_release_date": "2026-09-11T19:45:13.415000+00:00",
      "product_status:known_affected": "2",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: Linux kernel: Out-of-bounds memory access in NTFS via crafted boot sector",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89612.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-16T00:01:40Z",
      "cve": "CVE-2026-89612",
      "id": "CVE-2026-89612",
      "initial_release_date": "2026-09-16T00:01:40Z",
      "product_status:known_not_affected": "353",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-89612",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-89612.json",
      "version": "2"
    }
  }
}



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