{
  "cveId": "CVE-2026-64399",
  "url": "https://patchblox.com/security/cve/CVE-2026-64399",
  "summary": "CVE-2026-64399 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-64399, released July 26, 2026. It is not reported as exploited. Patch Radar priority: Urgent.",
  "title": "linux: In the Linux kernel, the following vulnerability has been resolved:  ksmbd: add permission checks for FSCTL_DUPLICATE...",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  ksmbd: add permission checks for FSCTL_DUPLICATE_EXTENTS_TO_FILE  The FSCTL_DUPLICATE_EXTENTS_TO_FILE arm of smb2_ioctl() overwrites the destination file\u0027s data via vfs_clone_file_range() with neither the share-level KSMBD_TREE_CONN_FLAG_WRITABLE check nor a per-handle fp-\u003Edaccess check that the other write-bearing arms carry. A client can overwrite destination data on a read-only share, or from a handle opened with only FILE_WRITE_ATTRIBUTES (which still yields an FMODE_WRITE filp). FILE_WRITE_ATTRIBUTES-only destination handle overwrote the file\u0027s data via the clone. Add both checks, matching the FSCTL_SET_SPARSE permission fix; require FILE_WRITE_DATA since this writes data.",
  "published": "2026-07-25T10:17:23Z",
  "severity": "critical",
  "cvss": 9.8,
  "cvssVector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
  "epss": 0.00491,
  "epssPercentile": 0.42486,
  "priority": "Urgent",
  "priorityTier": 2,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 12.15 (bookworm)",
      "fixedVersion": "6.1.180-1",
      "fix": "DEBIAN-CVE-2026-64399",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-64399",
      "released": "2026-07-26T13:52:50Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "6.12.96-1",
      "fix": "DEBIAN-CVE-2026-64399",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-64399",
      "released": "2026-07-26T13:52:50Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "7.1.4-1",
      "fix": "DEBIAN-CVE-2026-64399",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-64399",
      "released": "2026-07-26T13:52:50Z"
    },
    {
      "platform": "linux",
      "product": "linux-6.12",
      "release": "Debian 12.15 (bookworm)",
      "fixedVersion": "6.12.100-1~deb12u1",
      "fix": "DEBIAN-CVE-2026-64399",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-64399",
      "released": "2026-07-26T13:52:50Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-09T01:18:40Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}