---
id: CVE-2021-42554
title: >-
  An issue was discovered in Insyde InsydeH2O with Kernel 5.0 before 05.08.42,
  Kernel 5.1 before 05.16.42, Kernel 5.2 before 05.26.42, Kernel 5.3 before
  05.35.42, Kernel 5.4 before 05.42.51, and Kernel 5.5 before 05.50.51
summary: >-
  An issue was discovered in Insyde InsydeH2O with Kernel 5.0 before 05.08.42,
  Kernel 5.1 before 05.16.42, Kernel 5.2 before 05.26.42, Kernel 5.3 before
  05.35.42, Kernel 5.4 before 05.42.51, and Kernel 5.5 before 05.50.51. An SMM
  memory co…
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'
cwe:
  - CWE-787
vendor: insyde
product: insydeh2o
affected:
  - 'insydeh2o >= 5.0, < 5.08.42'
  - 'insydeh2o >= 5.1, < 5.16.42'
  - 'insydeh2o >= 5.2, < 5.26.42'
  - 'insydeh2o >= 5.3, < 5.35.42'
  - 'insydeh2o >= 5.4, < 5.42.51'
  - 'insydeh2o >= 5.5, < 5.50.51'
  - simatic_field_pg_m5_firmware
  - simatic_field_pg_m6_firmware
  - simatic_ipc127e_firmware
  - simatic_ipc227g_firmware
  - simatic_ipc277g_firmware
  - simatic_ipc327g_firmware
  - simatic_ipc377g_firmware
  - simatic_ipc427e_firmware
  - simatic_ipc477e_firmware
  - simatic_ipc627e_firmware
  - simatic_ipc647e_firmware
  - simatic_ipc677e_firmware
  - simatic_ipc847e_firmware
  - simatic_itp1000_firmware
  - ruggedcom_ape1808_firmware
patched:
  - insydeh2o 5.50.51
published: '2022-02-03'
updated: '2026-08-11'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2021-42554'
references:
  - url: 'https://cert-portal.siemens.com/productcert/pdf/ssa-306654.pdf'
    label: cve@mitre.org
  - url: 'https://security.netapp.com/advisory/ntap-20220216-0007/'
    label: cve@mitre.org
  - url: 'https://www.insyde.com/security-pledge'
    label: cve@mitre.org
  - url: 'https://www.insyde.com/security-pledge/SA-2022012'
    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-20220216-0007/'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://www.insyde.com/security-pledge'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://www.insyde.com/security-pledge/SA-2022012'
    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: 0.00327
epssPercentile: 0.23136
ingestedAt: '2026-08-11T16:47:02.264Z'
---

## Overview

An issue was discovered in Insyde InsydeH2O with Kernel 5.0 before 05.08.42, Kernel 5.1 before 05.16.42, Kernel 5.2 before 05.26.42, Kernel 5.3 before 05.35.42, Kernel 5.4 before 05.42.51, and Kernel 5.5 before 05.50.51. An SMM memory corruption vulnerability in FvbServicesRuntimeDxe allows a possible attacker to write fixed or predictable data to SMRAM. Exploiting this issue could lead to escalating privileges to SMM.

## Affected

- `insydeh2o >= 5.0, < 5.08.42`
- `insydeh2o >= 5.1, < 5.16.42`
- `insydeh2o >= 5.2, < 5.26.42`
- `insydeh2o >= 5.3, < 5.35.42`
- `insydeh2o >= 5.4, < 5.42.51`
- `insydeh2o >= 5.5, < 5.50.51`
- `simatic_field_pg_m5_firmware`
- `simatic_field_pg_m6_firmware`
- `simatic_ipc127e_firmware`
- `simatic_ipc227g_firmware`
- `simatic_ipc277g_firmware`
- `simatic_ipc327g_firmware`
- `simatic_ipc377g_firmware`
- `simatic_ipc427e_firmware`
- `simatic_ipc477e_firmware`
- `simatic_ipc627e_firmware`
- `simatic_ipc647e_firmware`
- `simatic_ipc677e_firmware`
- `simatic_ipc847e_firmware`
- `simatic_itp1000_firmware`
- `ruggedcom_ape1808_firmware`

## Remediation

Upgrade past the affected range:

- `insydeh2o 5.50.51`