---
id: CVE-2026-89738
title: >-
  kernel: usb: gadget: at91_udc: drain polled-VBUS timer/work before udc is
  freed (CVE-2026-89738)
summary: >-
  A flaw was found in the Linux kernel's `at91_udc` USB gadget driver. In
  polled-VBUS mode, a timing issue during driver unbinding or probe failure can
  lead to a use-after-free vulnerability. A local attacker could exploit this by
  triggering…
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: vendor
cwe: CWE-825
vendor: Red Hat
product: Red Hat OpenShift Container Platform 4
affected:
  - openshift_container_platform 4
published: '2026-09-11'
updated: '2026-09-21'
sourceUpdated: '2026-09-21T17:28:12+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89738.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89738.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89738'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532232'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89738'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89738'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89738.mbox
  - url: 'https://git.kernel.org/stable/c/51a311eb97e91ce1aed3005cb71ccb2e30f8cce8'
  - url: 'https://git.kernel.org/stable/c/557ef547d49ff5e6026a4d39bdd3113bd81d7688'
  - url: 'https://git.kernel.org/stable/c/a2a602cb1e28d76a5398cec3fa21b0110385f501'
  - url: 'https://git.kernel.org/stable/c/c27d13ce4bab80fbdf6523928071b6c24b37606c'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
  - score-dispute
epss: 0.00175
epssPercentile: 0.06235
scores:
  vendor: 4.1
  cna: 7.8
ingestedAt: '2026-09-14T15:23:07.472Z'
---

## Overview

A flaw was found in the Linux kernel's `at91_udc` USB gadget driver. In polled-VBUS mode, a timing issue during driver unbinding or probe failure can lead to a use-after-free vulnerability. A local attacker could exploit this by triggering a normal driver unbind operation, which may interleave with an already queued work item. This could result in system instability or a denial of service (DoS) due to the driver attempting to access freed memory.

## Vendor advisories

- **Red Hat VEX** · Moderate · updated 2026-09-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89738.json)

**kernel: usb: gadget: at91_udc: drain polled-VBUS timer/work before udc is freed** — rated Moderate by Red Hat. Released 2026-09-11, updated 2026-09-21.

Not affected:

- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4

## Remediation

Refer to the advisory for fix availability.