Is CVE-2021-41840 in the CISA KEV catalog?

No. CVE-2021-41840 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-41840?

CVE-2021-41840 has a CVSS v3 base score of 8.2 (HIGH).

What is the EPSS score for CVE-2021-41840?

CVE-2021-41840 has an EPSS score of 0.30% (22th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-41840?

Upgrade insydeh2o to 5.40.35 or later.

CVE & CISA-KEV Catalog

CVE-2021-41840

HIGH

8.2

CVSS v3

NVD

Description

An issue was discovered in NvmExpressDxe in the kernel 5.0 through 5.5 in Insyde InsydeH2O. There is an SMM callout that allows an attacker to access the System Management Mode and execute arbitrary code. This occurs because of Inclusion of Functionality from an Untrusted Control Sphere.

CWE-770Allocation of Resources Without Limits or Throttling

How to fix

Remediation Available

insydeh2oNVD

Affected:>= 5.4, < 5.40.35Fixed in:5.40.35CVE-2021-41840derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorLocal

Attack ComplexityLow

Privileges RequiredHigh

User InteractionNone

ScopeChanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

Exploit Intelligence

0.30%probability of exploitation in 30 days

22ndpercentile

Low risk: more likely to be exploited than 22% of all known CVEs.

References

Vendor Advisory2

Third-Party Advisory2

Other references1

kb.cert.org

Related Vulnerabilities

Other CWE-770 (Allocation of Resources Without Limits or Throttling) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2023-50387	High	7.5	100%	-	Fix
CVE-2019-11478	Medium	5.3	95%	-	Fix
CVE-2019-11479	High	7.5	92%	-	Fix
CVE-2024-27316	High	7.5	91%	-	Fix
CVE-2022-30522	High	7.5	90%	-	Fix
CVE-2019-9515	High	7.5	88%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-11-04.