# CVE-2026-98456: Bluetooth: mgmt: fix race in read_unconf_index_list()

> A race condition in the Linux kernel Bluetooth management allows an out-of-bounds write, potentially leading to code execution or denial of service.

- **Severity:** High 7.0 (`CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 18 Oct 2026
- **Updated:** 24 Oct 2026
- **Also known as:** AZL-108825, BELL-CVE-2026-98456, DEBIAN-CVE-2026-98456, GHSA-79jp-j4mv-p57c, UBUNTU-CVE-2026-98456

## What is CVE-2026-98456?

CVE-2026-98456 is a high-severity vulnerability in Linux, published on 18 Oct 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

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.

## Which versions are affected by CVE-2026-98456?


## How do I fix CVE-2026-98456?

Apply the vendor's patch.

## Is CVE-2026-98456 being exploited?

There is no known exploitation of CVE-2026-98456 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98456 and fix it if it is affected.

What it is: CVE-2026-98456 is a high-severity vulnerability in Linux, published on 18 Oct 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-98456 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-98456/ (Markdown: https://insights.sbomify.com/CVE-2026-98456/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98456
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98456
- OSV: https://osv.dev/vulnerability/CVE-2026-98456

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98456/
Summaries are generated and may contain mistakes; the official description above is the record.