{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "6ceb4cc81ef3409ff79dcb959771f9110787397a"
            },
            {
              "fixed": "e4c36dfac57a7261e9aeb0f3a7f30944a8aefb56"
            },
            {
              "fixed": "d5803e3345dae9c6470bb61869885236276b9a35"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "7.1.0"
            },
            {
              "fixed": "7.1.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72209.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nntfs: validate attribute values on lookup\n\nntfs_attr_find() and ntfs_external_attr_find() check that generic\nresident attribute values fit in their attribute records and that\nfixed-size resident values are large enough. For variable-length resident\nformats, however, the fixed part is not enough: embedded length fields\ncan still point callers past the resident value.\n\nA crafted image can set a small resident $FILE_NAME value_length while\nleaving file_name_length large. Callers then trust file_name_length and\nread past the resident value when converting or comparing the name. This\nwas reproduced with a crafted image under KASAN as a slab-out-of-bounds\nread from the kmalloc-1k MFT record copy. The stack included\nntfs_lookup(), ntfs_iget(), ntfs_read_locked_inode(), ntfs_attr_name_get(),\nntfs_ucstonls(), and utf16s_to_utf8s().\n\nAdd a shared attribute value validator and use it before a lookup path\ncan return an attribute, including the AT_UNUSED enumeration case where\ncallers inspect returned attributes directly. The helper validates\nresident value bounds, minimum resident value sizes, variable-length\n$FILE_NAME fields, and non-resident mapping-pairs metadata that was\npreviously checked separately in both lookup paths.\n\nThis also preserves the intended resident @val matching semantics in the\nexternal attribute lookup path. The old duplicated validation block\noverwrote the actual resident value length with the type-specific minimum\nlength before comparing @val, so variable-length resident values could\nfail to match even when the bytes were identical. Keep the comparison on\nthe actual value length, and make ntfs_attrlist_entry_add() compare\nresident attributes with lowest_vcn zero instead of reading the\nnon-resident union member after a successful resident match.\n\nReject non-resident $FILE_NAME records too: the format requires\n$FILE_NAME to be resident and callers treat returned records as resident.",
  "id": "CVE-2026-72209",
  "modified": "2026-08-18T03:31:13.156889239Z",
  "published": "2026-08-15T05:54:04.772Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d5803e3345dae9c6470bb61869885236276b9a35"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e4c36dfac57a7261e9aeb0f3a7f30944a8aefb56"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72209.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72209"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "ntfs: validate attribute values on lookup"
}