# CVE-2023-52456: serial: imx: fix tx statemachine deadlock

> A deadlock in the Linux kernel's i.MX serial driver can render the RS485 interface unusable if the port is closed during transmission.

- **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:** 23 Feb 2024
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2023-52456, DEBIAN-CVE-2023-52456, GHSA-53gx-3hrh-cr29, UBUNTU-CVE-2023-52456

## What is CVE-2023-52456?

CVE-2023-52456 is a medium-severity denial of service vulnerability in Linux kernel, published on 23 Feb 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:

serial: imx: fix tx statemachine deadlock

When using the serial port as RS485 port, the tx statemachine is used to
control the RTS pin to drive the RS485 transceiver TX_EN pin. When the
TTY port is closed in the middle of a transmission (for instance during
userland application crash), imx_uart_shutdown disables the interface
and disables the Transmission Complete interrupt. afer that,
imx_uart_stop_tx bails on an incomplete transmission, to be retriggered
by the TC interrupt. This interrupt is disabled and therefore the tx
statemachine never transitions out of SEND. The statemachine is in
deadlock now, and the TX_EN remains low, making the interface useless.

imx_uart_stop_tx now checks for incomplete transmission AND whether TC
interrupts are enabled before bailing to be retriggered. This makes sure
the state machine handling is reached, and is properly set to
WAIT_AFTER_SEND.

Weakness: CWE-667 (Improper Locking)

## Which versions are affected by CVE-2023-52456?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2023-52456?

Apply the vendor's patch.

## Is CVE-2023-52456 being exploited?

There is no known exploitation of CVE-2023-52456 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-2023-52456 and fix it if it is affected.

What it is: CVE-2023-52456 is a medium-severity denial of service vulnerability in Linux kernel, published on 23 Feb 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-2023-52456 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-2023-52456/ (Markdown: https://insights.sbomify.com/CVE-2023-52456/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-52456
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-52456
- OSV: https://osv.dev/vulnerability/CVE-2023-52456

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-52456/
Summaries are generated and may contain mistakes; the official description above is the record.