# CVE-2026-99008: Bluetooth: RFCOMM: Fix NULL tty_dev dereference in rfcomm_dev_shutdown


- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 23 Oct 2026
- **Updated:** 23 Oct 2026
- **Also known as:** AZL-110852, BELL-CVE-2026-99008, DEBIAN-CVE-2026-99008, GHSA-5xf6-vj9w-8fx6, UBUNTU-CVE-2026-99008

## What is CVE-2026-99008?

CVE-2026-99008 is a vulnerability in Linux, published on 23 Oct 2026. 

### Official description

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

Bluetooth: RFCOMM: Fix NULL tty_dev dereference in rfcomm_dev_shutdown

syzbot hit a NULL pointer dereference in rfcomm_dev_shutdown() when an
RFCOMM tty is closed.

rfcomm_dev_add() puts the new device on rfcomm_dev_list first and only
then registers the tty device and saves it in dev->tty_dev. If that
registration fails, dev->tty_dev is never set at all. The device can be
looked up in the meantime, so an open() of /dev/rfcommN gets through
rfcomm_tty_install() and attaches to it. When that tty is closed again,
rfcomm_dev_shutdown() uses dev->tty_dev without checking it:

  Oops: general protection fault, probably for non-canonical address
  KASAN: null-ptr-deref in range [0x0000000000000040-0x0000000000000047]
  RIP: 0010:rfcomm_dev_shutdown+0x48/0xb0 net/bluetooth/rfcomm/tty.c:131
  Call Trace:
   tty_port_shutdown+0x1bf/0x220 drivers/tty/tty_port.c:372
   tty_port_close+0x4e/0x150 drivers/tty/tty_port.c:705
   tty_release+0x359/0x1670 drivers/tty/tty_io.c:1718
   __fput+0x418/0xa50 fs/file_table.c:512

rfcomm_dev_destruct() already copes with a NULL dev->tty_dev. Add the
same check to rfcomm_dev_shutdown(), so the tty device is only moved
when it was actually registered.

## Which versions are affected by CVE-2026-99008?


## How do I fix CVE-2026-99008?

Upgrade to a fixed version.

## Is CVE-2026-99008 being exploited?

There is no known exploitation of CVE-2026-99008 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-99008 and fix it if it is affected.

What it is: CVE-2026-99008 is a vulnerability in Linux, published on 23 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-99008 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-2026-99008/ (Markdown: https://insights.sbomify.com/CVE-2026-99008/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-99008
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-99008
- OSV: https://osv.dev/vulnerability/CVE-2026-99008

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-99008/
Summaries are generated and may contain mistakes; the official description above is the record.