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7.8High

Insyde Insydeh2o

CVE-2021-33626

A vulnerability exists in SMM (System Management Mode) branch that registers a SWSMI handler that does not sufficiently check or validate the allocated buffer pointer(QWORD values for CommBuffer). This can be used by an attacker to corrupt data in SMRAM memory and even lead to arbitrary code execution.

What this means for your business

  • It affects Insydeh2o. It matters if your company, or a supplier that handles your data, runs it.
  • An attacker can use it only with access to the machine itself, with an ordinary user login, and without anyone at your company clicking anything.
  • FIRST's prediction model gives it a 0.3% chance of attack attempts being seen in the next 30 days, ranking above 23% of all known flaws.

What to do

  1. 1Check whether your company or your suppliers run Insydeh2o, and which version. The affected versions are listed further down this page.
  2. 2If you do, apply the vendor's fix. A patch or vendor advisory has been published.

Not sure if your company is exposed?

Fastnexa’s certified penetration testers can check whether attackers could use this flaw, or others like it, against your websites, apps and network. The full test is free for our first 10 founding clients until 31 December 2026.

Check if you’re exposedBook a call

Scoring

CVSS
7.8 (v3.1)
Vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-829
Assigned by
cve@mitre.org

Dates

Published
2021-10-01
Last modified
2026-08-11
Sources
NVD

Affected products

  • Insyde Insydeh2o5.3 - 5.34.44, 5.2 - 5.25.44, 5.1 - 5.16.25, 5.4 - 5.42.44, 5.3 - 5.35.25, 5.2 - 5.26.25, 5.4 - 5.43.25
  • Siemens Ruggedcom Apr1808 Firmwareall versions
  • Siemens Ruggedcom Apr1808all versions
  • Siemens Simatic Field Pg M5 Firmwareall versions
  • Siemens Simatic Field Pg M5all versions
  • Siemens Simatic Field Pg M6 Firmwareall versions
  • Siemens Simatic Field Pg M6all versions
  • Siemens Simatic Ipc127e Firmwareall versions
  • Siemens Simatic Ipc127eall versions
  • Siemens Simatic Ipc227g Firmwareall versions
  • Siemens Simatic Ipc227gall versions
  • Siemens Simatic Ipc277g Firmwareall versions

As listed in the NVD configuration data. Not a statement about your estate.

References