{
  "cveId": "CVE-2026-98809",
  "url": "https://patchblox.com/security/cve/CVE-2026-98809",
  "summary": "CVE-2026-98809 is fixed in 12 products on 1 platform, first by DEBIAN-CVE-2026-98809, released October 19, 2026. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "Bluetooth: hci_sync: don\u0027t drain cmd_sync backlog on unregister",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  Bluetooth: hci_sync: don\u0027t drain cmd_sync backlog on unregister  hci_unregister_dev() disables cmd_work and cmd_timer, then calls hci_cmd_sync_clear(), whose cancel_work_sync() waits for hci_cmd_sync_work() to return. That worker dequeues and runs every entry on cmd_sync_work_list. With cmd_work disabled nothing reaches the controller, so each queued HCI command waits the full HCI_CMD_TIMEOUT (2s).  The backlog has no bound. Userspace can keep queuing MGMT commands such as MGMT_OP_GET_CLOCK_INFO against a controller that doesn\u0027t answer. Closing /dev/vhci then blocks in vhci_release() for backlog * 2s:    INFO: task syz-executor:5749 blocked for more than 143 seconds.    cancel_work_sync    hci_cmd_sync_clear    hci_unregister_dev    vhci_release  In a local reproduction the backlog held more than 5000 entries, which comes to hours of hang.  Stop the worker from taking new entries once HCI_UNREGISTER is set, and wake any request still waiting with -ENODEV before cancelling the work. The entries left over are destroyed with -ECANCELED by the existing sweep in hci_cmd_sync_clear(). They stay on the list until the work has stopped, so hci_cmd_sync_dequeue() and friends still see them. A callback already running may still issue another command, which delays unregister by at most one timeout per remaining command, not by the whole backlog.",
  "published": "2026-10-18T16:17:34Z",
  "severity": "Moderate",
  "cvss": 5.5,
  "epss": 0.00173,
  "epssPercentile": 0.06768,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "vendorAdvisory": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-98809",
  "fixes": [
    {
      "platform": "linux",
      "product": "kernel-64kb",
      "release": "sles 15.7",
      "fixedVersion": "6.4.0-150700.53.90.1",
      "fix": "SUSE-SU-2026:5091-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-5091-1",
      "released": "2026-11-07T00:43:02Z"
    },
    {
      "platform": "linux",
      "product": "kernel-azure",
      "release": "sles 15.7",
      "fixedVersion": "6.4.0-150700.53.90.1",
      "fix": "SUSE-SU-2026:5091-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-5091-1",
      "released": "2026-11-07T00:43:02Z"
    },
    {
      "platform": "linux",
      "product": "kernel-default",
      "release": "sles 15.7",
      "fixedVersion": "6.4.0-150700.53.90.1",
      "fix": "SUSE-SU-2026:5091-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-5091-1",
      "released": "2026-11-07T00:43:02Z"
    },
    {
      "platform": "linux",
      "product": "kernel-default-base",
      "release": "sles 15.7",
      "fixedVersion": "6.4.0-150700.53.90.1.150700.17.51.1",
      "fix": "SUSE-SU-2026:5091-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-5091-1",
      "released": "2026-11-07T00:43:02Z"
    },
    {
      "platform": "linux",
      "product": "kernel-docs",
      "release": "sles 15.7",
      "fixedVersion": "6.4.0-150700.53.90.1",
      "fix": "SUSE-SU-2026:5091-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-5091-1",
      "released": "2026-11-07T00:43:02Z"
    },
    {
      "platform": "linux",
      "product": "kernel-livepatch-SLE15-SP7_Update_24",
      "release": "sles 15.7",
      "fixedVersion": "1-150700.15.3.1",
      "fix": "SUSE-SU-2026:5091-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-5091-1",
      "released": "2026-11-07T00:43:02Z"
    },
    {
      "platform": "linux",
      "product": "kernel-obs-build",
      "release": "sles 15.7",
      "fixedVersion": "6.4.0-150700.53.90.1",
      "fix": "SUSE-SU-2026:5091-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-5091-1",
      "released": "2026-11-07T00:43:02Z"
    },
    {
      "platform": "linux",
      "product": "kernel-source",
      "release": "sles 15.7",
      "fixedVersion": "6.4.0-150700.53.90.1",
      "fix": "SUSE-SU-2026:5091-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-5091-1",
      "released": "2026-11-07T00:43:02Z"
    },
    {
      "platform": "linux",
      "product": "kernel-syms",
      "release": "sles 15.7",
      "fixedVersion": "6.4.0-150700.53.90.1",
      "fix": "SUSE-SU-2026:5091-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-5091-1",
      "released": "2026-11-07T00:43:02Z"
    },
    {
      "platform": "linux",
      "product": "kernel-zfcpdump",
      "release": "sles 15.7",
      "fixedVersion": "6.4.0-150700.53.90.1",
      "fix": "SUSE-SU-2026:5091-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-5091-1",
      "released": "2026-11-07T00:43:02Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "6.12.113-1",
      "fix": "DEBIAN-CVE-2026-98809",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-98809",
      "released": "2026-10-19T16:27:52Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "7.2.10-1",
      "fix": "DEBIAN-CVE-2026-98809",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-98809",
      "released": "2026-10-19T16:27:52Z"
    },
    {
      "platform": "linux",
      "product": "linux-6.12",
      "release": "Debian 12.15 (bookworm)",
      "fixedVersion": "6.12.113-1~deb12u1",
      "fix": "DEBIAN-CVE-2026-98809",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-98809",
      "released": "2026-10-19T16:27:52Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T00:53:09Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}