---
id: CVE-2026-10663
title: >-
  In Zephyr's experimental USB host stack (CONFIG_USB_HOST_STACK),
  usbh_device_disconnect() (subsys/usb/host/usbh_device.c) freed the root
  usb_device slab object without clearing the cached pointer ctx->root
summary: >-
  In Zephyr's experimental USB host stack (CONFIG_USB_HOST_STACK),
  usbh_device_disconnect() (subsys/usb/host/usbh_device.c) freed the root
  usb_device slab object without clearing the cached pointer ctx->root. The bus
  removal handler dev_re…
severity: medium
cvss: 6.1
cvssVector: 'CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H'
cwe:
  - CWE-416
published: '2026-07-12'
updated: '2026-07-12'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-10663'
references:
  - url: >-
      https://github.com/zephyrproject-rtos/zephyr/commit/4b87a8f161a44cb19505fa97db7cf72f64d49165
    label: vulnerabilities@zephyrproject.org
  - url: >-
      https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-26q8-xjq3-f5p6
    label: vulnerabilities@zephyrproject.org
tags:
  - nvd
ingestedAt: '2026-07-12T17:20:29.543Z'
epss: 0.00236
epssPercentile: 0.14945
---

## Overview

In Zephyr's experimental USB host stack (CONFIG_USB_HOST_STACK), usbh_device_disconnect() (subsys/usb/host/usbh_device.c) freed the root usb_device slab object without clearing the cached pointer ctx->root. The bus removal handler dev_removed_handler() (subsys/usb/host/usbh_core.c) decides what to tear down solely from ctx->root, checking only that it is non-NULL.

Because UHC controller drivers (e.g. uhc_max3421e, uhc_mcux_common) synthesize UHC_EVT_DEV_REMOVED directly from physical bus line state with no debounce or state guard, an attacker with physical USB access (or a rogue device that bounces its connection) can deliver a second device-removed event after a root device disconnect. The handler then re-enters usbh_device_disconnect() with the dangling pointer, locking a mutex inside the freed object (use-after-free), removing the freed node from the device list, and calling k_mem_slab_free() on the already-freed block (double-free). If the slab block has been reissued to a newly attached device in between, this corrupts a live object.

Impact is denial of service (crash) and memory corruption; the attack vector is physical/local. The flaw was introduced in v4.4.0 by the connect/disconnect refactor and is fixed by clearing ctx->root in usbh_device_disconnect() before freeing.

## Remediation

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