---
id: CVE-2026-89732
title: >-
  kernel: usb: gadget: f_fs: Prevent deadlock during ep0 read loop
  (CVE-2026-89732)
summary: >-
  A flaw was found in the Linux kernel's USB FunctionFS (f_fs) module. A local
  attacker could exploit a deadlock vulnerability in the ffs_ep0_read()
  function. This occurs when a userspace daemon polls ep0 and the USB gadget is
  simultaneously…
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-833
vendor: Red Hat
product: Red Hat OpenShift Container Platform 4
affected:
  - openshift_container_platform 4
published: '2026-09-11'
updated: '2026-09-21'
sourceUpdated: '2026-09-21T17:27:57+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89732.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89732.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89732'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532293'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89732'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89732'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89732.mbox
  - url: 'https://git.kernel.org/stable/c/34e88f53614640b59039a46717fb6142e9871022'
  - url: 'https://git.kernel.org/stable/c/569dd7e5dcffe1e1c6b26ca2cd3be57eb433e082'
  - url: 'https://git.kernel.org/stable/c/eac233e63f9db82ba874e3cccafaafab162999e0'
  - url: 'https://git.kernel.org/stable/c/fd20cc68bbdb5620696ac108e8f2efd180fe2c1a'
  - url: 'https://git.kernel.org/stable/c/fbe3db4b650c284df8eb4cb68eebcf270cf861b5'
  - url: 'https://git.kernel.org/stable/c/30430509c156e1df2bdafd5f1cadb160e53db5d6'
  - url: 'https://git.kernel.org/stable/c/bafddd0f20b5228760be303aa69c58502e92309c'
  - url: 'https://git.kernel.org/stable/c/b0a6bfac0c3c3edf5b2ecaee87a09234601fe78d'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
epss: 0.00236
epssPercentile: 0.13011
ingestedAt: '2026-09-14T15:23:07.449Z'
---

## Overview

A flaw was found in the Linux kernel's USB FunctionFS (f_fs) module. A local attacker could exploit a deadlock vulnerability in the ffs_ep0_read() function. This occurs when a userspace daemon polls ep0 and the USB gadget is simultaneously torn down, causing the kernel to enter an unresponsive state. This can lead to a denial of service (DoS).

## Vendor advisories

- **Red Hat VEX** · Moderate · updated 2026-09-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89732.json)

**kernel: usb: gadget: f_fs: Prevent deadlock during ep0 read loop** — 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.