CVE-2021-33627 — Security Box Score

CVE · referencelatest edition

Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2021-33627HIGH

n/a n/a — An issue was discovered in Insyde InsydeH2O Kernel 5.0 before 05.09.11, 5.1 before 05.17.11, 5.2 before 05.27.11, 5.3 before 05.36.11, 5.…

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   L   L   H   N  C  H  H  H    8.2   .0033   25.8     —

AFFECTED
  Product  Versions  Fixed
  n/a      n/a –     —

TIMELINE
  May 28  Reserved by mitre
  Feb 3   Published (CNA: mitre)
  Aug 11  ENRICHED — CVE-2021-33627. Received CVSS 8.2 and CPE data from NVD.

CWE-119 · CNA: mitre · CVSS v3.1 · 6 references · NVD status: Modified

Description

An issue was discovered in Insyde InsydeH2O Kernel 5.0 before 05.09.11, 5.1 before 05.17.11, 5.2 before 05.27.11, 5.3 before 05.36.11, 5.4 before 05.44.11, and 5.5 before 05.52.11 affecting FwBlockServiceSmm. Software SMI services that use the Communicate() function of the EFI_SMM_COMMUNICATION_PROTOCOL do not check whether the address of the buffer is valid, which allows use of SMRAM, MMIO, or OS kernel addresses.

Lifecycle

Complete event history — 3 events, chronological
Date	Event	Detail
May 28, 2021	Reserved	Reserved by mitre
February 3, 2022	Published	Published (CNA: mitre)
August 11, 2026	ENRICHED	ENRICHED — CVE-2021-33627. Received CVSS 8.2 and CPE data from NVD.

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
n/a	n/a	—	n/a	—

Weaknesses

CWE-119

References (6)

https://cert-portal.siemens.com/productcert/html/ssa-306654.html
https://cert-portal.siemens.com/productcert/pdf/ssa-306654.pdf [Third Party Advisory]
https://security.netapp.com/advisory/ntap-20220222-0002/ [Third Party Advisory]
https://www.insyde.com/security-pledge [Vendor Advisory]
https://www.insyde.com/security-pledge/SA-2022022 [Vendor Advisory]
https://www.kb.cert.org/vuls/id/796611

Authoritative record: CVE-2021-33627 at cve.org

Weaknesses: CWE-119

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2021-33627 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.