CVE-2026-90133 (GCVE-0-2026-90133)

Vulnerability from cvelistv5 – Published: 2026-09-17 16:06 – Updated: 2026-09-18 17:53
VLAI
Title
ntfs: Fix index_root heap OOB write in ntfs_ir_to_ib()
Summary
In the Linux kernel, the following vulnerability has been resolved: ntfs: Fix index_root heap OOB write in ntfs_ir_to_ib() ntfs_ir_to_ib copies all entries from index_root into a freshly allocated index_block_size-byte buffer without verifying that the entries fit in the available space. The entries in index_root may be larger than the usable entry space in the index block. This can cause OOB writes past the end of the allocation. The validator ntfs_index_root_inconsistent() checks that entries are self-consistent within the IR value, but never cross-checks them against index_block_size. There is no bounds check in ntfs_ir_to_ib() before the memcpy. Fixing this at the sink in ntfs_ir_to_ib() since ntfs_index_root_inconsistent() validates the logical consistency of index_root as a structure and a root with large entries is a structurally valid root. The bug is a size conflict of ntfs_ir_to_ib(). Also, the validator is called once per inode load in ntfs_read_locked_inode() while ntfs_ir_to_ib() is only called during a reparent, a check there adds no overhead to the common path. Moreover, even a future call path that bypasses the validator would still be protected. With NULL as first parameter of ntfs_error(), the volume error flag is never set by this call, so the device name will be absent from the error message. In any case, that the caller, ntfs_ir_reparent(), prints an error message that includes the device name on NULL returns. I think this is the best solution available without adding 'struct super_block *sb' as a parameter to ntfs_ir_to_ib(). This heap out-of-bounds write is triggered by a crafted filesystem image, which is not in the kernel threat model, anyway, fixing memory errors would be nice to keep things secure.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 0a8ac0c1fa0b99a5b29002bc7f232ed7eafddef0 , < 825dec5120933e90c54e30e31ccfa6c3449043a8 (git)
Affected: 0a8ac0c1fa0b99a5b29002bc7f232ed7eafddef0 , < dc09bf79b76f9a7157e225f449655f3f62f96c9c (git)
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Linux Linux Affected: 7.1
Unaffected: 0 , < 7.1 (semver)
Unaffected: 7.2.6 , ≤ 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/index.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "status": "affected",
              "version": "0a8ac0c1fa0b99a5b29002bc7f232ed7eafddef0",
              "versionType": "git"
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              "status": "affected",
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              "versionType": "git"
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          "vendor": "Linux",
          "versions": [
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              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
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          "nodes": [
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              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.6",
                  "versionStartIncluding": "7.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc1",
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              "operator": "OR"
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nntfs: Fix index_root heap OOB write in ntfs_ir_to_ib()\n\nntfs_ir_to_ib copies all entries from index_root into a freshly allocated\nindex_block_size-byte buffer without verifying that the entries fit in the\navailable space. The entries in index_root may be larger than the usable\nentry space in the index block.\n\nThis can cause OOB writes past the end of the allocation.\n\nThe validator ntfs_index_root_inconsistent() checks that entries are\nself-consistent within the IR value, but never cross-checks them against\nindex_block_size. There is no bounds check in ntfs_ir_to_ib() before the\nmemcpy.\n\nFixing this at the sink in ntfs_ir_to_ib() since\nntfs_index_root_inconsistent() validates the logical consistency of\nindex_root as a structure and a root with large entries is a structurally\nvalid root. The bug is a size conflict of ntfs_ir_to_ib().\nAlso, the validator is called once per inode load in\nntfs_read_locked_inode() while ntfs_ir_to_ib() is only called during a\nreparent, a check there adds no overhead to the common path.\nMoreover, even a future call path that bypasses the validator would still\nbe protected.\n\nWith NULL as first parameter of ntfs_error(), the volume error flag is\nnever set by this call, so the device name will be absent from the error\nmessage. In any case, that the caller, ntfs_ir_reparent(), prints an error\nmessage that includes the device name on NULL returns.\nI think this is the best solution available without adding\n\u0027struct super_block *sb\u0027 as a parameter to ntfs_ir_to_ib().\n\nThis heap out-of-bounds write is triggered by a crafted filesystem image,\nwhich is not in the kernel threat model, anyway, fixing memory errors would\nbe nice to keep  things secure."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The overflow source is on-disk $INDEX_ROOT (ir-\u003eindex_block_size and the resident entries) that ntfs_ir_to_ib() memcpy()s; the trigger is vfs_create/mkdir/link/rename \u2192 ntfs_create/__ntfs_link \u2192 ntfs_index_add_filename \u2192 ntfs_ie_add \u2192 ntfs_ir_make_space \u2192 ntfs_ir_reparent. No protocol message carries those fields.\nAC:L - ntfs_read_locked_inode() accepts any power-of-two index_block_size in [512, PAGE_SIZE] and ntfs_index_root_inconsistent() never compares entry bytes to that size, so a 512-byte IB plus a packed resident INDEX_ROOT in a full MFT record makes ntfs_ir_truncate() return -ENOSPC and ntfs_ir_reparent() run on the next create, with no race.\nPR:N - mount_capable() needs init-namespace CAP_SYS_ADMIN because ntfs_fs_type lacks FS_USERNS_MOUNT; that mount is the victim or udisks2/vold action (UI:R), not attacker privilege. After mount, ntfs_create() is an ordinary VFS create on a directory whose mode the image controls, so the attacker needs no account.\nUI:R - ntfs_ir_to_ib() is called only from ntfs_ir_reparent(), not from ntfs_fill_super(), so attaching the volume is not enough. A victim or automounter must mount the attacker-supplied NTFS image, and then create/mkdir/link/rename must add a filename so ntfs_ie_add() takes the ENOSPC reparent path.\nS:U - The kvzalloc(index_block) overflow in ntfs_ir_to_ib() corrupts host-kernel heap in the same OS authority as fs/ntfs; it is in-kernel memory corruption, not a VM escape, IOMMU bypass, or sandbox breakout.\nC:H - memcpy() in ntfs_ir_to_ib() writes attacker-controlled INDEX_ROOT entry bytes (UTF-16 names, MFT refs) past the kvzalloc(ir-\u003eindex_block_size) object into adjacent slab, a heap OOB write that can be groomed to disclose neighboring kernel objects.\nI:H - The same memcpy is an unbounded heap out-of-bounds write of attacker-chosen index-entry contents past the allocated index_block, which can corrupt adjacent slab objects and hijack kernel control flow.\nA:H - Writing past the kvzalloc index_block into unmapped or poisoned adjacent heap oopses or panics on the ntfs_ir_reparent() create/mkdir path, fully denying availability even when the overflow is not turned into a write primitive."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-18T17:53:15.758Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
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          "url": "https://git.kernel.org/stable/c/825dec5120933e90c54e30e31ccfa6c3449043a8"
        },
        {
          "url": "https://git.kernel.org/stable/c/dc09bf79b76f9a7157e225f449655f3f62f96c9c"
        }
      ],
      "title": "ntfs: Fix index_root heap OOB write in ntfs_ir_to_ib()",
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  "cveMetadata": {
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-90133",
    "datePublished": "2026-09-17T16:06:33.234Z",
    "dateReserved": "2026-09-11T19:38:34.788Z",
    "dateUpdated": "2026-09-18T17:53:15.758Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2",
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      "date": "2026-09-26",
      "epss": "0.00205",
      "percentile": "0.09365"
    },
    "nvd": {
      "cve": {
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                "product": "Linux",
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                ],
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                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
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                    "version": "7.1"
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                    "versionType": "semver"
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                    "status": "unaffected",
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                  }
                ]
              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nntfs: Fix index_root heap OOB write in ntfs_ir_to_ib()\n\nntfs_ir_to_ib copies all entries from index_root into a freshly allocated\nindex_block_size-byte buffer without verifying that the entries fit in the\navailable space. The entries in index_root may be larger than the usable\nentry space in the index block.\n\nThis can cause OOB writes past the end of the allocation.\n\nThe validator ntfs_index_root_inconsistent() checks that entries are\nself-consistent within the IR value, but never cross-checks them against\nindex_block_size. There is no bounds check in ntfs_ir_to_ib() before the\nmemcpy.\n\nFixing this at the sink in ntfs_ir_to_ib() since\nntfs_index_root_inconsistent() validates the logical consistency of\nindex_root as a structure and a root with large entries is a structurally\nvalid root. The bug is a size conflict of ntfs_ir_to_ib().\nAlso, the validator is called once per inode load in\nntfs_read_locked_inode() while ntfs_ir_to_ib() is only called during a\nreparent, a check there adds no overhead to the common path.\nMoreover, even a future call path that bypasses the validator would still\nbe protected.\n\nWith NULL as first parameter of ntfs_error(), the volume error flag is\nnever set by this call, so the device name will be absent from the error\nmessage. In any case, that the caller, ntfs_ir_reparent(), prints an error\nmessage that includes the device name on NULL returns.\nI think this is the best solution available without adding\n\u0027struct super_block *sb\u0027 as a parameter to ntfs_ir_to_ib().\n\nThis heap out-of-bounds write is triggered by a crafted filesystem image,\nwhich is not in the kernel threat model, anyway, fixing memory errors would\nbe nice to keep  things secure."
          }
        ],
        "id": "CVE-2026-90133",
        "lastModified": "2026-09-18T18:17:43.133",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 7.8,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "REQUIRED",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
                "version": "3.1"
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              "exploitabilityScore": 1.8,
              "impactScore": 5.9,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
            }
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        "published": "2026-09-17T17:17:05.837",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/825dec5120933e90c54e30e31ccfa6c3449043a8"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/dc09bf79b76f9a7157e225f449655f3f62f96c9c"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-21T16:32:38Z",
      "cve": "CVE-2026-90133",
      "id": "CVE-2026-90133",
      "initial_release_date": "2026-09-18T00:20:56Z",
      "product_status:known_not_affected": "347",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-90133",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-90133.json",
      "version": "4"
    }
  }
}



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