# CVE-2026-53073: Bluetooth: hci_ldisc: Clear HCI_UART_PROTO_INIT on error

> A null pointer dereference in the Linux kernel Bluetooth driver allows local attackers to cause a system crash via UART data processing errors.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **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:** 24 Jun 2026
- **Updated:** 24 Jun 2026
- **Also known as:** BELL-CVE-2026-53073, DEBIAN-CVE-2026-53073, GHSA-wq7c-9cj9-76jg, ROOT-OS-DEBIAN-11-CVE-2026-53073, ROOT-OS-DEBIAN-12-CVE-2026-53073, ROOT-OS-UBUNTU-2204-CVE-2026-53073, ROOT-OS-UBUNTU-2404-CVE-2026-53073, UBUNTU-CVE-2026-53073

## What is CVE-2026-53073?

CVE-2026-53073 is a medium-severity vulnerability in Linux kernel, published on 24 Jun 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_ldisc: Clear HCI_UART_PROTO_INIT on error

When hci_register_dev() fails in hci_uart_register_dev()
HCI_UART_PROTO_INIT is not cleared before calling hu->proto->close(hu)
and setting hu->hdev to NULL. This means incoming UART data will reach
the protocol-specific recv handler in hci_uart_tty_receive() after
resources are freed.

Clear HCI_UART_PROTO_INIT with a write lock before calling
hu->proto->close() and setting hu->hdev to NULL. The write lock ensures
all active readers have completed and no new reader can enter the
protocol recv path before resources are freed.

This allows the protocol-specific recv functions to remove the
"HCI_UART_REGISTERED" guard without risking a null pointer dereference
if hci_register_dev() fails.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2026-53073?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-53073?

Apply the vendor's patch.

## Is CVE-2026-53073 being exploited?

There is no known exploitation of CVE-2026-53073 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-53073 and fix it if it is affected.

What it is: CVE-2026-53073 is a medium-severity vulnerability in Linux kernel, published on 24 Jun 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-2026-53073 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2026-53073/ (Markdown: https://insights.sbomify.com/CVE-2026-53073/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53073
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53073
- OSV: https://osv.dev/vulnerability/CVE-2026-53073

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-53073/
Summaries are generated and may contain mistakes; the official description above is the record.