---
id: CVE-2026-89621
title: >-
  kernel: HID: mcp2221: validate report size in mcp2221_raw_event()
  (CVE-2026-89621)
summary: >-
  A flaw was found in the Linux kernel's HID (Human Interface Device) mcp2221
  driver. A malicious USB device can exploit this vulnerability by sending a
  specially crafted, short HID report with an invalid size. This can cause the
  system to r…
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-125
vendor: Red Hat
product: Red Hat OpenShift Container Platform 4
affected:
  - openshift_container_platform 4
published: '2026-09-11'
updated: '2026-09-18'
sourceUpdated: '2026-09-18T22:37:14+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89621.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89621.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89621'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532406'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89621'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89621'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89621.mbox
  - url: 'https://git.kernel.org/stable/c/127de5919820f88a9d55e8371ad4ac49f625f4c5'
  - url: 'https://git.kernel.org/stable/c/2c9a6998c19503626c57a2267bf279e204113079'
  - url: 'https://git.kernel.org/stable/c/7c18fb36708a97ff6772825cc087b6d537bbf0d5'
  - url: 'https://git.kernel.org/stable/c/bdc6a3af0dd734a326acdb7d6401a3b6a9f4f149'
  - url: 'https://git.kernel.org/stable/c/cb38b1f149b7143355b37e86c841acf0076e5c2a'
  - url: 'https://git.kernel.org/stable/c/b2c67dc0e30c308647bbd9b9e5d69a44c9d2733d'
  - url: 'https://git.kernel.org/stable/c/fffcfa367072628c3144cca17d2a3c3c9e50c057'
  - url: 'https://git.kernel.org/stable/c/c1c508e8923911cb458234997e55b7a4b9aa066f'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
epss: 0.0022
epssPercentile: 0.11134
ingestedAt: '2026-09-14T15:23:07.450Z'
---

## Overview

A flaw was found in the Linux kernel's HID (Human Interface Device) mcp2221 driver. A malicious USB device can exploit this vulnerability by sending a specially crafted, short HID report with an invalid size. This can cause the system to read past valid memory, leading to the disclosure of sensitive kernel memory to userspace through the I2C/SMBus read path. This information disclosure could potentially expose confidential system data.

## Vendor advisories

- **Red Hat VEX** · Moderate · updated 2026-09-18 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89621.json)

**kernel: HID: mcp2221: validate report size in mcp2221_raw_event()** — rated Moderate by Red Hat. Released 2026-09-11, updated 2026-09-18.

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.