# CVE-2024-46706: tty: serial: fsl_lpuart: mark last busy before uart_add_one_port

> A race condition in the fsl_lpuart driver can cause a kernel boot hang when specific debug boot arguments are used, preventing system startup.

- **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:** 13 Sep 2024
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2024-46706, DEBIAN-CVE-2024-46706, GHSA-gggx-8wfw-w6jx, UBUNTU-CVE-2024-46706

## What is CVE-2024-46706?

CVE-2024-46706 is a medium-severity denial of service vulnerability in Linux kernel, published on 13 Sep 2024. 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:

tty: serial: fsl_lpuart: mark last busy before uart_add_one_port

With "earlycon initcall_debug=1 loglevel=8" in bootargs, kernel
sometimes boot hang. It is because normal console still is not ready,
but runtime suspend is called, so early console putchar will hang
in waiting TRDE set in UARTSTAT.

The lpuart driver has auto suspend delay set to 3000ms, but during
uart_add_one_port, a child device serial ctrl will added and probed with
its pm runtime enabled(see serial_ctrl.c).
The runtime suspend call path is:
device_add
     |-> bus_probe_device
           |->device_initial_probe
	           |->__device_attach
                         |-> pm_runtime_get_sync(dev->parent);
			 |-> pm_request_idle(dev);
			 |-> pm_runtime_put(dev->parent);

So in the end, before normal console ready, the lpuart get runtime
suspended. And earlycon putchar will hang.

To address the issue, mark last busy just after pm_runtime_enable,
three seconds is long enough to switch from bootconsole to normal
console.

## Which versions are affected by CVE-2024-46706?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2024-46706?

Apply the vendor's patch.

## Is CVE-2024-46706 being exploited?

There is no known exploitation of CVE-2024-46706 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-2024-46706 and fix it if it is affected.

What it is: CVE-2024-46706 is a medium-severity denial of service vulnerability in Linux kernel, published on 13 Sep 2024. 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-2024-46706 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-2024-46706/ (Markdown: https://insights.sbomify.com/CVE-2024-46706/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-46706
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-46706
- OSV: https://osv.dev/vulnerability/CVE-2024-46706

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-46706/
Summaries are generated and may contain mistakes; the official description above is the record.