Is CVE-2021-43323 in the CISA KEV catalog?

No. CVE-2021-43323 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-43323?

CVE-2021-43323 has a CVSS v3 base score of 8.2 (HIGH).

What is the EPSS score for CVE-2021-43323?

CVE-2021-43323 has an EPSS score of 0.35% (27th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-43323?

Upgrade insydeh2o to 5.51.45 or later.

CVE & CISA-KEV Catalog

CVE-2021-43323

HIGH

8.2

CVSS v3

NVD

Description

An issue was discovered in UsbCoreDxe in Insyde InsydeH2O with kernel 5.5 before 05.51.45, 5.4 before 05.43.45, 5.3 before 05.35.45, 5.2 before 05.26.45, 5.1 before 05.16.45, and 5.0 before 05.08.45. An SMM callout vulnerability allows an attacker to hijack execution flow of code running in System Management Mode. Exploiting this issue could lead to escalating privileges to SMM.

How to fix

Remediation Available

insydeh2oNVD

Affected:>= 5.5, < 5.51.45Fixed in:5.51.45CVE-2021-43323derived 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

0.35%probability of exploitation in 30 days

27thpercentile

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

References

Vendor Advisory1

insyde.com

Third-Party Advisory2

Other references1

kb.cert.org

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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.