Is CVE-2021-42059 in the CISA KEV catalog?

No. CVE-2021-42059 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-42059?

CVE-2021-42059 has a CVSS v3 base score of 6.7 (MEDIUM).

What is the EPSS score for CVE-2021-42059?

CVE-2021-42059 has an EPSS score of 0.34% (27th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-42059?

Upgrade insydeh2o to 5.42.20 or later.

CVE & CISA-KEV Catalog

CVE-2021-42059

MEDIUM

6.7

CVSS v3

NVD

Description

An issue was discovered in Insyde InsydeH2O Kernel 5.0 before 05.08.41, Kernel 5.1 before 05.16.41, Kernel 5.2 before 05.26.41, Kernel 5.3 before 05.35.41, and Kernel 5.4 before 05.42.20. A stack-based buffer overflow leads toarbitrary code execution in UEFI DisplayTypeDxe DXE driver.

CWE-787Out-of-bounds Write

How to fix

Remediation Available

insydeh2oNVD

Affected:>= 5.4, < 5.42.20Fixed in:5.42.20CVE-2021-42059derived 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

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Exploit Intelligence

0.34%probability of exploitation in 30 days

27thpercentile

Low risk: more likely to be exploited than 27% of all known CVEs.

References

Vendor Advisory2

Third-Party Advisory2

Other references1

kb.cert.org

Related Vulnerabilities

Other CWE-787 (Out-of-bounds Write) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2025-22457	Critical	9.0	100%	KEV + Ransom	Fix
CVE-2025-0282	Critical	9.0	100%	KEV + Ransom	-
CVE-2015-3113	Critical	9.8	100%	KEV	Fix
CVE-2021-20038	Critical	9.8	100%	KEV + Ransom	-
CVE-2023-4863	High	8.8	100%	KEV	Fix
CVE-2020-16040	Medium	6.5	100%	-	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.