ntfs: Fix index_root heap OOB write in ntfs_ir_to_ib()

{
  "id": "a4f958dbba7805e75aa85a1ffdec6c6db431b11bb07a1594462bd530cd583262",
  "url": "https://osv.dev/vulnerability/CVE-2026-90133",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "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 w",
    "evidence": "osv:CVE-2026-90133",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "7.2.6",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-90133",
      "aliases": [
        "CVE-2026-90133"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0a8ac0c1fa0b99a5b29002bc7f232ed7eafddef0"
                },
                {
                  "fixed": "825dec5120933e90c54e30e31ccfa6c3449043a8"
                },
                {
                  "fixed": "dc09bf79b76f9a7157e225f449655f3f62f96c9c"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90133.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "7.1.0"
                },
                {
                  "fixed": "7.2.6"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90133.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:38.576385970Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/825dec5120933e90c54e30e31ccfa6c3449043a8",
        "https://git.kernel.org/stable/c/dc09bf79b76f9a7157e225f449655f3f62f96c9c",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90133.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-90133",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90133.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-90133",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 506242,
  "published_at": "2026-09-17T16:06:33.234+00:00"
}