ntfs: bound $AttrDef table walk to the loaded table size

{
  "id": "6ffef165acbd5d497c97a6f56c8a16256e554547630374d0492d0e9eaa94090f",
  "url": "https://osv.dev/vulnerability/CVE-2026-98136",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ntfs: bound $AttrDef table walk to the loaded table size",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: ntfs: bound $AttrDef table walk to the loaded table size ntfs_attr_find_in_attrdef() walks the in-memory $AttrDef table, but the loop condition bounds only the start of each entry, not the whole entry: for (ad = vol->attrdef; (u8 *)ad - (u8 *)vol->attrdef < vol->attrdef_size && ad->type; ++ad) struct attr_def is 160 bytes; the guard reads ad->type at offset 128 and the loop body reads further fields. vol->attrdef is kvzalloc(i_size), where i_size is the on-disk $AttrDef data size, checked in load_and_init_attrdef() only as 0 < i_size <= 0x7fffffff. A volume whose $AttrDef data size is smaller than one entry (e.g. 120 bytes) makes the read of ad->type run past the allocation. Creating a file reaches this through ntfs_attr_size_bounds_check() and reads out of bounds: BUG: KASAN: slab-out-of-bounds in ntfs_attr_find_in_attrdef+0x66/0xa0 Read of size 4 at addr ffff888005833280 by task init/1 ntfs_attr_find_in_attrdef ntfs_attr_size_bounds_check ntfs_attr_can_be_non_resident ntfs_attr_add Require the whole entry to lie within attrdef_size in the loop guard, and reject at mount a $AttrDef too small to hold one attr_def entry.",
    "evidence": "osv:CVE-2026-98136",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "7.2.7",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-98136",
      "aliases": [
        "CVE-2026-98136"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "1e9ea7e04472d4e5e12e58c881eaacfb3e49b669"
                },
                {
                  "fixed": "3e2ae47b8ebc632c27e7843a4632d9a7c060885e"
                },
                {
                  "fixed": "c8504fc1245f5322af5fa5c325ab05f9cf792b87"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98136.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "7.1.0"
                },
                {
                  "fixed": "7.2.7"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98136.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:28.188828954Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/3e2ae47b8ebc632c27e7843a4632d9a7c060885e",
        "https://git.kernel.org/stable/c/c8504fc1245f5322af5fa5c325ab05f9cf792b87",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98136.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-98136",
        "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/2026/98xxx/CVE-2026-98136.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-98136",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 494950,
  "published_at": "2026-09-25T10:36:14.106+00:00"
}