ntfs: fix u16 truncation of restart-area length check

{
  "id": "e6244d4a4ed301e1e56061c97bbe7217499ca8b81d9c9a8fef55549cd3b330ad",
  "url": "https://osv.dev/vulnerability/CVE-2026-80672",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ntfs: fix u16 truncation of restart-area length check",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: ntfs: fix u16 truncation of restart-area length check ntfs_check_restart_area() validates that the $LogFile restart area and its trailing log client record array fit within the system page size: u16 ra_ofs, ra_len, ca_ofs; ... ra_len = ca_ofs + le16_to_cpu(ra->log_clients) * sizeof(struct log_client_record); if (ra_ofs + ra_len > le32_to_cpu(rp->system_page_size) || ...) return false; ra_len is u16, but the right-hand side is computed in size_t (sizeof(struct log_client_record) == 160). Both ca_ofs and log_clients come straight from the on-disk restart area. With an on-disk log_clients of 410 the product 410 * 160 = 65600; adding ca_ofs and storing into the u16 ra_len truncates modulo 65536 (e.g. ca_ofs 64 gives ra_len 128), so the \"fits in the page\" check passes even though the client array described by log_clients extends far beyond the page. ntfs_check_log_client_array() then walks the array bounded only by the on-disk log_clients count: cr = ca + idx; if (cr->prev_client != LOGFILE_NO_CLIENT) ... For log_clients 410 it dereferences records up to ca + 409 * 160, ~64 KiB past the kvzalloc(system_page_size) restart-page buffer -- an out-of-bounds read of attacker-controlled extent, reachable when a crafted NTFS image is mounted (load_and_check_logfile() at mount time). This is the in-kernel analogue of CVE-2022-30789, fixed in the ntfs-3g userspace driver but never in this revived classic driver. Compute the",
    "evidence": "osv:CVE-2026-80672",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "7.1.5",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-80672",
      "aliases": [
        "CVE-2026-80672"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/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": "1e9ea7e04472d4e5e12e58c881eaacfb3e49b669"
                },
                {
                  "fixed": "07a4751ef3ccc8bfd17bfbb16e5003c03161790d"
                },
                {
                  "fixed": "390936fb15053d8d8991ca3a22776e251a5a7f2f"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-80672.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "7.1.0"
                },
                {
                  "fixed": "7.1.5"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-80672.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:49.053440208Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/07a4751ef3ccc8bfd17bfbb16e5003c03161790d",
        "https://git.kernel.org/stable/c/390936fb15053d8d8991ca3a22776e251a5a7f2f",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80672.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-80672",
        "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/2026/80xxx/CVE-2026-80672.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-80672",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 517566,
  "published_at": "2026-08-28T06:49:12.34+00:00"
}