{
  "cveId": "CVE-2026-72422",
  "url": "https://patchblox.com/security/cve/CVE-2026-72422",
  "summary": "CVE-2026-72422 is fixed in linux on 1 platform, first by DEBIAN-CVE-2026-72422, released August 15, 2026. It is not reported as exploited. Patch Radar priority: Urgent.",
  "title": "linux: In the Linux kernel, the following vulnerability has been resolved:  ksmbd: fix use-after-free of conn-\u003Epreauth_info...",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  ksmbd: fix use-after-free of conn-\u003Epreauth_info in concurrent SMB2 NEGOTIATE  conn-\u003Epreauth_info is shared connection state (struct preauth_integrity_info, kmalloc-96) that is allocated and freed by the SMB2 NEGOTIATE handler and read by the response send path.  smb2_handle_negotiate() allocates conn-\u003Epreauth_info, and on a deassemble_neg_contexts() failure kfrees it and sets it to NULL. Both the allocation and the free/NULL happen under ksmbd_conn_lock(conn) (the connection srv_mutex), which is held across the whole handler body.  The response send path smb3_preauth_hash_rsp(), called from the send: block of __handle_ksmbd_work(), reads conn-\u003Epreauth_info and dereferences conn-\u003Epreauth_info-\u003EPreauth_HashValue (via ksmbd_gen_preauth_integrity_hash()) without taking conn_lock. When a client drives two SMB2 NEGOTIATE requests on the same connection, one worker can free conn-\u003Epreauth_info on the failing-negotiate path while a concurrent send-path worker is reading it, producing a slab use-after-free read (KASAN-confirmed).  The send-path read tested conn-\u003Epreauth_info for NULL but raced with the free that occurs between the NULL check and the dereference, so the NULL guard alone does not close the window.  Serialize the NEGOTIATE-branch read in smb3_preauth_hash_rsp() under ksmbd_conn_lock(conn) and re-check conn-\u003Epreauth_info inside the lock. Because the negotiate handler holds conn_lock across its kfree \u002B NULL assignment, a reader that also takes conn_lock either runs fully before the allocation or fully after the NULL store, and can never observe the freed-but-not-yet-NULLed pointer. ksmbd_gen_preauth_integrity_hash() takes no locks itself (it only computes a SHA-512 over the buffer), so no lock-ordering inversion is introduced, and conn_lock is a sleepable mutex which is safe on this send path (it already performs network I/O).",
  "published": "2026-08-15T06:22:15Z",
  "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": 0.00717,
  "epssPercentile": 0.54074,
  "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-2026-72422",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-72422",
      "released": "2026-08-15T22:38:55Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "6.12.100-1",
      "fix": "DEBIAN-CVE-2026-72422",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-72422",
      "released": "2026-08-15T22:38:55Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "7.1.5-1",
      "fix": "DEBIAN-CVE-2026-72422",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-72422",
      "released": "2026-08-15T22:38:55Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-09T13:31:49Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}