---
id: CVE-2026-98809
title: >-
  kernel: Bluetooth: hci_sync: don't drain cmd_sync backlog on unregister
  (CVE-2026-98809)
summary: >-
  A flaw was found in the Linux kernel's Bluetooth subsystem. When unregistering
  a Bluetooth device, pending synchronous commands are processed without
  reaching the controller, causing each queued request to wait for a full
  timeout. A local …
severity: medium
cvss: 4.4
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H'
cvssSource: vendor
cwe: CWE-770
vendor: Red Hat
product: Red Hat Enterprise Linux 9
affected:
  - enterprise_linux 10
  - enterprise_linux 8
  - enterprise_linux 9
  - openshift_container_platform 4
published: '2026-10-18'
updated: '2026-10-23'
sourceUpdated: '2026-10-23T17:29:11+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98809.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98809.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-98809'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2555226'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-98809'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-98809'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98809.mbox
  - url: 'https://git.kernel.org/stable/c/b11acfcb5925ed27fae692b27931a1ac732677fb'
  - url: 'https://git.kernel.org/stable/c/143bde97c4101ae68eb656c87e620c45b07a3090'
  - url: 'https://git.kernel.org/stable/c/7f16443a30f4e86d84ae4faf057d333b41ddb757'
  - url: 'https://git.kernel.org/stable/c/e8ba8c9c74d1035042cdf6cb5adf8f59b9b1271c'
  - url: 'https://git.kernel.org/stable/c/b1f24c1ab52345e810c42a1a81286cb5a7c92252'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
epss: 0.00168
epssPercentile: 0.05981
ingestedAt: '2026-10-18T16:47:32.478Z'
---

## Overview

A flaw was found in the Linux kernel's Bluetooth subsystem. When unregistering a Bluetooth device, pending synchronous commands are processed without reaching the controller, causing each queued request to wait for a full timeout. A local user can exploit this issue by queuing an unbounded number of commands, leading to prolonged task hangs and causing a Denial of Service (DoS).

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-10-23 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98809.json)

**kernel: Bluetooth: hci_sync: don't drain cmd_sync backlog on unregister** — rated Moderate by Red Hat. Released 2026-10-18, updated 2026-10-23.

Affected:

- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4

No fix planned:

- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4

Not affected:

- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat OpenShift Container Platform 4

## Remediation

Fix deferred