# CVE-2026-97977: Bluetooth: btusb: Fix UAF of btusb_data by rx_work

> A use-after-free in the Linux kernel Bluetooth USB driver allows attackers with physical or local access to execute arbitrary code or crash the system.

- **Severity:** Not scored
- **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:** 25 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-104853, BELL-CVE-2026-97977, DEBIAN-CVE-2026-97977, GHSA-mvpx-42x3-8643, UBUNTU-CVE-2026-97977

## What is CVE-2026-97977?

CVE-2026-97977 is an use after free vulnerability in Linux, published on 25 Sep 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: btusb: Fix UAF of btusb_data by rx_work

btusb_close() and btusb_flush() cancel data->rx_work with the
asynchronous cancel_delayed_work(), so if btusb_rx_work() is already
running on another CPU it keeps running after the cancel returns.

btusb_disconnect() calls hci_unregister_dev(), which invokes
btusb_close(), and then frees the btusb_data. A still running
btusb_rx_work() then dereferences the freed data:

	while ((skb = skb_dequeue(&data->acl_q)))
		data->recv_acl(data->hdev, skb);

Use cancel_delayed_work_sync() instead. In btusb_close() the cancel also
has to happen after btusb_stop_traffic(), otherwise an URB completion
racing with the cancel can requeue the work right after it has been
waited for.

## Which versions are affected by CVE-2026-97977?


## How do I fix CVE-2026-97977?

Apply the vendor's patch.

## Is CVE-2026-97977 being exploited?

There is no known exploitation of CVE-2026-97977 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-97977 and fix it if it is affected.

What it is: CVE-2026-97977 is an use after free vulnerability in Linux, published on 25 Sep 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-2026-97977 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-2026-97977/ (Markdown: https://insights.sbomify.com/CVE-2026-97977/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-97977
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-97977
- OSV: https://osv.dev/vulnerability/CVE-2026-97977

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-97977/
Summaries are generated and may contain mistakes; the official description above is the record.