---
id: CVE-2026-10674
title: >-
  DoS (hard fault) in NXP LPUART driver: unsupported runtime UART config leaves
  clocks disabled
summary: >-
  The NXP LPUART serial driver (drivers/serial/uart_mcux_lpuart.c), when
  CONFIG_UART_USE_RUNTIME_CONFIGURE is enabled, called LPUART_Deinit() at the
  start of mcux_lpuart_configure(), which disables the LPUART peripheral clocks.
  The request…
severity: medium
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
cvssSource: cna
cwe:
  - CWE-617
vendor: zephyrproject
product: zephyr
affected:
  - zephyr >= 3.7.0 < 4.3.1
  - zephyr >= 4.4.0 < 4.4.2
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-07-22T19:32:08.144813Z'
published: '2026-07-21'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T22:10:16.575Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-10674'
references:
  - url: >-
      https://github.com/zephyrproject-rtos/zephyr/commit/f56935c46fdf6559a20ad8484b29896ecac5808f
    label: Fix commit
  - url: >-
      https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-mw68-r353-m3vf
    label: GHSA-mw68-r353-m3vf
tags:
  - cve.org
epss: 0.00143
epssPercentile: 0.03185
ingestedAt: '2026-10-15T22:48:25.570Z'
---

## Overview

The NXP LPUART serial driver (drivers/serial/uart_mcux_lpuart.c), when CONFIG_UART_USE_RUNTIME_CONFIGURE is enabled, called LPUART_Deinit() at the start of mcux_lpuart_configure(), which disables the LPUART peripheral clocks. The requested configuration is validated only afterwards (in mcux_lpuart_configure_basic), and unsupported parity/data-bit/stop-bit/flow-control values return -ENOTSUP before the clock is re-enabled.

As a result, a uart_configure() request with an unsupported configuration left the LPUART in a clock-disabled state; any subsequent access to LPUART registers (poll_out/poll_in, interrupt handling, or a later reconfigure) faults on the gated peripheral and escalates to a hard fault, crashing the system.

uart_configure() is a Zephyr syscall whose verifier (z_vrfy_uart_configure) only checks that cfg is readable user memory and forwards the caller-supplied configuration unchanged, so an unprivileged userspace thread with access to an LPUART device can deterministically trigger the fault, a persistent system-wide denial of service.

Introduced in v2.5.0 and present in all subsequent releases until this fix, which removes the LPUART_Deinit() call and instead only disables the transmitter/receiver, leaving the clock running.

## Affected

- `zephyr >= 3.7.0 < 4.3.1`
- `zephyr >= 4.4.0 < 4.4.2`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.