# CVE-2026-98246: Bluetooth: hci_sync: Serialize local codec list cleanup

> A race condition in the Linux kernel Bluetooth subsystem allows a local attacker to trigger a use-after-free, potentially causing a system crash or arbitrary code execution.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 6 Oct 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-106437, BELL-CVE-2026-98246, DEBIAN-CVE-2026-98246, GHSA-4jxq-xw37-v6h5, UBUNTU-CVE-2026-98246

## What is CVE-2026-98246?

CVE-2026-98246 is an use after free vulnerability in Linux, published on 6 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: hci_sync: Serialize local codec list cleanup

hci_dev_close_sync() clears hdev->local_codecs after releasing hdev->lock.
Codec list additions and both traversals in sco_sock_getsockopt() use that
lock, but the close path does not. A close and BT_CODEC query can therefore
interleave as follows:

  hci_dev_close_sync()          sco_sock_getsockopt()
                                hci_dev_lock()
                                fetch codec entry
  hci_codec_list_clear()
    kfree(entry)
                                read entry->id

The reader then accesses an entry which the close path has freed. KASAN

  BUG: KASAN: slab-use-after-free in sco_sock_getsockopt+0xfa0/0xfe0
  Read of size 1 at addr ffff8881001c3450
  Call Trace:
   sco_sock_getsockopt+0xfa0/0xfe0
   do_sock_getsockopt+0x537/0x7b0
   __sys_getsockopt+0xf2/0x170
  Allocated by task 92:
   hci_codec_list_add.isra.0+0x2c/0x440
   hci_read_codec_capabilities+0x224/0x590
   hci_read_supported_codecs+0x2c2/0x640
  Freed by task 92:
   kfree+0x131/0x3c0
   hci_codec_list_clear+0xd8/0x160
   hci_dev_close_sync+0x92a/0xfa0

Take hdev->lock around the clear operation at its existing point in the
close path. This makes the clear wait for active readers and prevents a new
traversal until the list is empty without changing teardown ordering.

## Which versions are affected by CVE-2026-98246?


## How do I fix CVE-2026-98246?

Apply the vendor's patch.

## Is CVE-2026-98246 being exploited?

There is no known exploitation of CVE-2026-98246 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98246 and fix it if it is affected.

What it is: CVE-2026-98246 is an use after free vulnerability in Linux, published on 6 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-2026-98246 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-2026-98246/ (Markdown: https://insights.sbomify.com/CVE-2026-98246/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98246
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98246
- OSV: https://osv.dev/vulnerability/CVE-2026-98246

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98246/
Summaries are generated and may contain mistakes; the official description above is the record.