{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "eb817368f50c1cbe1bd07044124aad7db6330e3a"
            },
            {
              "fixed": "bf460ad5958d506492de4524a656439da3f99c51"
            },
            {
              "fixed": "620d133d469295ee7c017ca6aafac335f65c4a5a"
            },
            {
              "fixed": "9b9cf7e65cbeaae1b6636144bacee611cdd7a5d6"
            },
            {
              "fixed": "baae7b39673ec21073a25e3d14f8feaada01d5df"
            },
            {
              "fixed": "c917e4522d251071dde9871b9142d8ea1186ebfe"
            },
            {
              "fixed": "388e4139db27a9e3612c9d356b826f5b1ff6a9e3"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "5.15.0"
            },
            {
              "fixed": "6.1.178"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.145"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.96"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.39"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.1.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64399.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: add permission checks for FSCTL_DUPLICATE_EXTENTS_TO_FILE\n\nThe FSCTL_DUPLICATE_EXTENTS_TO_FILE arm of smb2_ioctl() overwrites the\ndestination file's data via vfs_clone_file_range() with neither the\nshare-level KSMBD_TREE_CONN_FLAG_WRITABLE check nor a per-handle\nfp-\u003edaccess check that the other write-bearing arms carry. A client can\noverwrite destination data on a read-only share, or from a handle opened\nwith only FILE_WRITE_ATTRIBUTES (which still yields an FMODE_WRITE filp).\nFILE_WRITE_ATTRIBUTES-only destination handle overwrote the file's data via\nthe clone. Add both checks, matching the FSCTL_SET_SPARSE permission fix;\nrequire FILE_WRITE_DATA since this writes data.",
  "id": "CVE-2026-64399",
  "modified": "2026-07-28T03:56:07.815182855Z",
  "published": "2026-07-25T08:50:42.925Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/388e4139db27a9e3612c9d356b826f5b1ff6a9e3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/620d133d469295ee7c017ca6aafac335f65c4a5a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9b9cf7e65cbeaae1b6636144bacee611cdd7a5d6"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/baae7b39673ec21073a25e3d14f8feaada01d5df"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bf460ad5958d506492de4524a656439da3f99c51"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c917e4522d251071dde9871b9142d8ea1186ebfe"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64399.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64399"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.8.0",
  "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": "ksmbd: add permission checks for FSCTL_DUPLICATE_EXTENTS_TO_FILE"
}