No exploitation reportedFix available

CVE-2021-41842

Q: Is CVE-2021-41842 actively exploited?

Active exploitation of CVE-2021-41842 has not been confirmed. Its EPSS score was 1.5% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2021-41842?

CVE-2021-41842 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

No exploitation reported by the sources we read.

Published2022-01-06
Fixed in05.51.45 · 05.43.46 · 05.35.46 · 05.26.46 · 05.16.46 · 05.08.46

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

An issue was discovered in AtaLegacySmm in the kernel 5.0 before 05.08.46, 5.1 before 05.16.46, 5.2 before 05.26.46, 5.3 before 05.35.46, 5.4 before 05.43.46, and 5.5 before 05.51.45 in Insyde InsydeH2O. Code execution can occur because the SMI handler lacks a CommBuffer check.

Timeline

dates in UTC

2022-01-0600:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-41842?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-41842?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Insyde insydeh2o

Branch	Affected	Fixed in	Source
5.x	≥ 5.5, < 05.51.45	05.51.45	NVD
5.x	> 5.4, < 05.43.46	05.43.46	NVD
5.x	≥ 5.3, < 05.35.46	05.35.46	NVD
5.x	≥ 5.2, < 05.26.46	05.26.46	NVD
5.x	≥ 5.1, < 05.16.46	05.16.46	NVD
5.x	≥ 5.0, < 05.08.46	05.08.46	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Update Insyde insydeh2o to 05.51.45 · 05.43.46 · 05.35.46 · 05.26.46 · 05.16.46 · 05.08.46

Advisories and patches

www.insyde.comVendor Advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

NVDCVSS 3.19.8read 2026-10-23
NVDCVSS 2.07.5read 2026-10-23
FIRST EPSSEPSS score1.5 %2026-10-22

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published: 2022-01-06
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2021-41842?

Is CVE-2021-41842 actively exploited?

Active exploitation of CVE-2021-41842 has not been confirmed. Its EPSS score was 1.5% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-41842?

CVE-2021-41842 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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