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Vulnerability record · CVE-2021-33627 · published 3 February 2022

CVE-2021-33627: Insydeh2o memory buffer overflow vulnerability

Insyde · Insydeh2o

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.

8.2 CVSS 3.1 High EPSS 0.33% · top 76.6% CWE-119 · Memory buffer overflow
8.2CVSS 3.1 base score, v2 7.2
0.33%EPSS exploitation probability, 30 days
NoNot in CISA KEV
15Affected product versions listed by NVD
10References
11 Aug 2026Last modified by NVD

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.

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

Affected products

15 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
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://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
https://cert-portal.siemens.com/productcert/html/ssa-306654.html

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2021-33627), CISA KEV, FIRST EPSS (scores of 2026-09-29). This page is refreshed as NVD updates the record.