---
id: CVE-2026-108952
title: >-
  RT-Thread through 5.3.0 contains a memory corruption vulnerability in the
  legacy USB CDC virtual COM port driver that aliases rx_ringbuffer as a Serial
  V2 rt_serial_rx_fifo in _function_enable()
summary: >-
  RT-Thread through 5.3.0 contains a memory corruption vulnerability in the
  legacy USB CDC virtual COM port driver that aliases rx_ringbuffer as a Serial
  V2 rt_serial_rx_fifo in _function_enable(). A connected USB host configuring
  the CDC …
severity: medium
cvss: 4.6
cvssVector: 'CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-843
published: '2026-10-12'
updated: '2026-10-12'
sourceUpdated: '2026-10-12T13:17:28.150'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-108952'
references:
  - url: 'https://github.com/RT-Thread/rt-thread'
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/RT-Thread/rt-thread/blob/99428a1e7f7447955aa860f7c969273a12095b8f/components/legacy/usb/usbdevice/class/cdc_vcom.c#L518
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/RT-Thread/rt-thread/commit/ceef6e0ccd646aef61b907aeb9f29269d1caba50
    label: disclosure@vulncheck.com
  - url: 'https://github.com/RT-Thread/rt-thread/issues/11739'
    label: disclosure@vulncheck.com
  - url: 'https://github.com/RT-Thread/rt-thread/pull/11770'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/rt-thread-through-5.3.0-memory-corruption-via-usb-cdc-vcom-driver
    label: disclosure@vulncheck.com
tags:
  - nvd
ingestedAt: '2026-10-12T14:50:34.109Z'
---

## Overview

RT-Thread through 5.3.0 contains a memory corruption vulnerability in the legacy USB CDC virtual COM port driver that aliases rx_ringbuffer as a Serial V2 rt_serial_rx_fifo in _function_enable(). A connected USB host configuring the CDC device triggers writes past the ring buffer into struct vcom members and an invalid rt_free() on close, causing denial of service.

## Remediation

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