---
id: "CVE-2026-98456"
kind: "vulnerability"
aliases: ["CVE-2026-98456"]
title: "Linux kernel: Bluetooth mgmt race lets userspace write out of bounds"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["bluetooth", "infrastructure", "linux-kernel"]
not_affected_if: ["no-bluetooth-hardware"]
published_at: "2026-10-18T16:16:56+00:00"
first_seen_at: "2026-10-23T21:57:15+00:00"
updated_at: "2026-10-25T05:27:18+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98456", "first_seen_at": "2026-10-23T21:57:15+00:00"}]
---

# Linux kernel: Bluetooth mgmt race lets userspace write out of bounds

A race in the Linux kernel Bluetooth management interface can cause an out-of-bounds write when listing unconfigured controllers. The sources do not say what an attacker gets beyond memory corruption in the kernel.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- `uname -r` to see the running kernel version
- unknown whether the sources list affected kernel versions

## Fix

- Update the Linux kernel to a release that includes the upstream commit fixing read_unconf_index_list() (version unknown from sources)
- Reboot after the kernel update so the fix is active

## Timeline

- 2026-10-23T21:57:15+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-98456

## From the sources

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

Bluetooth: mgmt: fix race in read_unconf_index_list()

read_unconf_index_list() counts unconfigured controllers before allocating
its response, then checks the device flags again while filling it.

hci_dev_list_lock stabilizes list membership, but it does not serialize the
per-device flags. During asynchronous controller setup, the worker can set
HCI_UNCONFIGURED and clear HCI_SETUP between the two passes. A controller
omitted from the allocation count can then become eligible for the fill
pass, causing an out-of-bounds write to rp->index[].

Allocate space for every device on hci_dev_list. Since list membership
cannot change while hci_dev_list_lock is held, the response remains large
enough regardless of flag transitions. The reported count and response
length still include only eligible unconfigured controllers.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_