GHSA-5XF6-VJ9W-8FX6

Vulnerability from github – Published: 2026-10-23 15:31 – Updated: 2026-10-23 15:31
VLAI
Details

In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: RFCOMM: Fix NULL tty_dev dereference in rfcomm_dev_shutdown

syzbot hit a NULL pointer dereference in rfcomm_dev_shutdown() when an RFCOMM tty is closed.

rfcomm_dev_add() puts the new device on rfcomm_dev_list first and only then registers the tty device and saves it in dev->tty_dev. If that registration fails, dev->tty_dev is never set at all. The device can be looked up in the meantime, so an open() of /dev/rfcommN gets through rfcomm_tty_install() and attaches to it. When that tty is closed again, rfcomm_dev_shutdown() uses dev->tty_dev without checking it:

Oops: general protection fault, probably for non-canonical address KASAN: null-ptr-deref in range [0x0000000000000040-0x0000000000000047] RIP: 0010:rfcomm_dev_shutdown+0x48/0xb0 net/bluetooth/rfcomm/tty.c:131 Call Trace: tty_port_shutdown+0x1bf/0x220 drivers/tty/tty_port.c:372 tty_port_close+0x4e/0x150 drivers/tty/tty_port.c:705 tty_release+0x359/0x1670 drivers/tty/tty_io.c:1718 __fput+0x418/0xa50 fs/file_table.c:512

rfcomm_dev_destruct() already copes with a NULL dev->tty_dev. Add the same check to rfcomm_dev_shutdown(), so the tty device is only moved when it was actually registered.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-99008"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-23T13:17:23Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: RFCOMM: Fix NULL tty_dev dereference in rfcomm_dev_shutdown\n\nsyzbot hit a NULL pointer dereference in rfcomm_dev_shutdown() when an\nRFCOMM tty is closed.\n\nrfcomm_dev_add() puts the new device on rfcomm_dev_list first and only\nthen registers the tty device and saves it in dev-\u003etty_dev. If that\nregistration fails, dev-\u003etty_dev is never set at all. The device can be\nlooked up in the meantime, so an open() of /dev/rfcommN gets through\nrfcomm_tty_install() and attaches to it. When that tty is closed again,\nrfcomm_dev_shutdown() uses dev-\u003etty_dev without checking it:\n\n  Oops: general protection fault, probably for non-canonical address\n  KASAN: null-ptr-deref in range [0x0000000000000040-0x0000000000000047]\n  RIP: 0010:rfcomm_dev_shutdown+0x48/0xb0 net/bluetooth/rfcomm/tty.c:131\n  Call Trace:\n   tty_port_shutdown+0x1bf/0x220 drivers/tty/tty_port.c:372\n   tty_port_close+0x4e/0x150 drivers/tty/tty_port.c:705\n   tty_release+0x359/0x1670 drivers/tty/tty_io.c:1718\n   __fput+0x418/0xa50 fs/file_table.c:512\n\nrfcomm_dev_destruct() already copes with a NULL dev-\u003etty_dev. Add the\nsame check to rfcomm_dev_shutdown(), so the tty device is only moved\nwhen it was actually registered.",
  "id": "GHSA-5xf6-vj9w-8fx6",
  "modified": "2026-10-23T15:31:35Z",
  "published": "2026-10-23T15:31:34Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-99008"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/08e90633377f1b2567ab5ad6810b74c552246a07"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3fd5164bdb04635caa7942ddb554b0ec699a9433"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a661f401f83b8462f2d424e0a1a72b7681e92ea2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d0aef0b0374678153244f162df507106d728af39"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d5c372ad03330f02962d4860df4d355ab25487df"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}



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