---
id: CVE-2021-43323
title: >-
  An issue was discovered in UsbCoreDxe in Insyde InsydeH2O with kernel 5.5
  before 05.51.45, 5.4 before 05.43.45, 5.3 before 05.35.45, 5.2 before
  05.26.45, 5.1 before 05.16.45, and 5.0 before 05.08.45
summary: >-
  An issue was discovered in UsbCoreDxe in Insyde InsydeH2O with kernel 5.5
  before 05.51.45, 5.4 before 05.43.45, 5.3 before 05.35.45, 5.2 before
  05.26.45, 5.1 before 05.16.45, and 5.0 before 05.08.45. An SMM callout
  vulnerability allows a…
severity: high
cvss: 8.2
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H'
vendor: insyde
product: insydeh2o
affected:
  - 'insydeh2o >= 5.1, < 5.16.45'
  - 'insydeh2o >= 5.2, < 5.26.45'
  - 'insydeh2o >= 5.3, < 5.33.45'
  - 'insydeh2o >= 5.0, < 5.08.45'
  - 'insydeh2o >= 5.4, < 5.43.45'
  - 'insydeh2o >= 5.5, < 5.51.45'
patched:
  - insydeh2o 5.51.45
published: '2022-02-03'
updated: '2026-08-11'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2021-43323'
references:
  - url: 'https://cert-portal.siemens.com/productcert/pdf/ssa-306654.pdf'
    label: cve@mitre.org
  - url: 'https://security.netapp.com/advisory/ntap-20220217-0013/'
    label: cve@mitre.org
  - url: 'https://www.insyde.com/security-pledge'
    label: cve@mitre.org
  - url: 'https://cert-portal.siemens.com/productcert/pdf/ssa-306654.pdf'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://security.netapp.com/advisory/ntap-20220217-0013/'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://www.insyde.com/security-pledge'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://www.kb.cert.org/vuls/id/796611'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-306654.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
tags:
  - nvd
epss: 0.00351
epssPercentile: 0.28874
ingestedAt: '2026-08-11T16:47:02.299Z'
---

## Overview

An issue was discovered in UsbCoreDxe in Insyde InsydeH2O with kernel 5.5 before 05.51.45, 5.4 before 05.43.45, 5.3 before 05.35.45, 5.2 before 05.26.45, 5.1 before 05.16.45, and 5.0 before 05.08.45. An SMM callout vulnerability allows an attacker to hijack execution flow of code running in System Management Mode. Exploiting this issue could lead to escalating privileges to SMM.

## Affected

- `insydeh2o >= 5.1, < 5.16.45`
- `insydeh2o >= 5.2, < 5.26.45`
- `insydeh2o >= 5.3, < 5.33.45`
- `insydeh2o >= 5.0, < 5.08.45`
- `insydeh2o >= 5.4, < 5.43.45`
- `insydeh2o >= 5.5, < 5.51.45`

## Remediation

Upgrade past the affected range:

- `insydeh2o 5.51.45`