---
id: CVE-2026-98773
title: >-
  kernel: USB: cdc-acm: skip URB restart in port_shutdown if disconnected
  (CVE-2026-98773)
summary: >-
  A flaw was found in the Linux kernel's CDC ACM (Communications Device Class
  Abstract Control Model) USB driver. A timing race condition during device
  disconnection and port closure can lead to a use-after-free vulnerability when
  communicat…
severity: medium
cvss: 4.7
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H'
cvssSource: vendor
cwe: CWE-825
vendor: Red Hat
product: Red Hat Enterprise Linux 6
affected:
  - enterprise_linux 6
published: '2026-10-18'
updated: '2026-10-23'
sourceUpdated: '2026-10-23T08:07:15+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98773.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98773.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-98773'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2555078'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-98773'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-98773'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98773.mbox
  - url: 'https://git.kernel.org/stable/c/d86775e79838d7d2e38ccf506a7d0f8e2dd4d5d0'
  - url: 'https://git.kernel.org/stable/c/9742905d9ed5bf23ebe4c100dec80b6bc50fb522'
  - url: 'https://git.kernel.org/stable/c/a0ed07b5bbb2d8fcef86810453216070691816e7'
  - url: 'https://git.kernel.org/stable/c/420ca35af891d33522cc08504768ccd60a4c450a'
  - url: 'https://git.kernel.org/stable/c/dc614d6bc991740d41d5a99ac7765c4b675dda88'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
epss: 0.00168
epssPercentile: 0.05977
ingestedAt: '2026-10-18T16:47:32.491Z'
---

## Overview

A flaw was found in the Linux kernel's CDC ACM (Communications Device Class Abstract Control Model) USB driver. A timing race condition during device disconnection and port closure can lead to a use-after-free vulnerability when communication requests attempt to access already freed memory buffers. A local attacker could exploit this flaw to cause a Denial of Service (DoS) via a system crash or potentially achieve privilege escalation.

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 6 · no fix planned: Red Hat Enterprise Linux 6 · updated 2026-10-23 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98773.json)

**kernel: USB: cdc-acm: skip URB restart in port_shutdown if disconnected** — rated Moderate by Red Hat. Released 2026-10-18, updated 2026-10-23.

Affected:

- Red Hat Enterprise Linux 6

No fix planned:

- Red Hat Enterprise Linux 6

Not affected:

- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4

## Remediation

Out of support scope