CVE-2021-41839

An issue was discovered in NvmExpressDxe in the kernel 5.0 through 5.5 in Insyde InsydeH2O. Because of an Untrusted Pointer Dereference that causes SMM memory corruption, an attacker may be able to write fixed or predictable data to SMRAM. Exploiting this issue could lead to escalating privileges to SMM.

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 administrator 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 19% of all known flaws.

What to do

1Check whether your company or your suppliers run Insydeh2o, and which version. The affected versions are listed further down this page.
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.

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Scoring

CVSS: 8.2 (v3.1)
Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
Weakness: CWE-119
Assigned by: cve@mitre.org

Dates

Published: 2022-02-03
Last modified: 2026-08-11
Sources: NVD

Affected products

Insyde Insydeh2o5.1 - 5.16.25, 5.2 - 5.26.25, 5.3 - 5.35.25, 5.4 - 5.43.25, 5.5 - 5.51.25

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