CVE-2021-33627

Name: CVE-2021-33627
Creator: NVD / NIST
Published: 2022-02-03T02:15:06.983+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.2/10EPSS 0.33%

Last modified Jun 17, 2026

CVE-2021-33627 is a high-severity vulnerability rated 8.2/10 on the CVSS scale. 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.. EPSS estimates a 0.33% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

8.2/10

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

EPSS Probability

0.33%

24.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-119

Affected Software

Vendor	Product	Versions
Insyde	Insydeh2o	>= 5.0, < 5.08.29
Insyde	Insydeh2o	>= 5.1, < 5.16.29
Insyde	Insydeh2o	>= 5.2, < 5.26.29
Insyde	Insydeh2o	>= 5.3, < 5.35.29
Siemens	Simatic Field Pg M5 Firmware	All versions
Siemens	Simatic Field Pg M6 Firmware	All versions
Siemens	Simatic Ipc127e Firmware	All versions
Siemens	Simatic Ipc227g Firmware	All versions
Siemens	Simatic Ipc277g Firmware	All versions
Siemens	Simatic Ipc327g Firmware	All versions
Siemens	Simatic Ipc377g Firmware	All versions
Siemens	Simatic Ipc427e Firmware	All versions
Siemens	Simatic Ipc477e Firmware	All versions
Siemens	Simatic Ipc627e Firmware	All versions
Siemens	Simatic Ipc647e Firmware	All versions
Siemens	Simatic Ipc677e Firmware	All versions
Siemens	Simatic Ipc847e Firmware	All versions
Siemens	Simatic Itp1000 Firmware	All versions

References

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

Timeline

Published: Feb 3, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-33627?

How severe is CVE-2021-33627?

CVE-2021-33627 has a CVSS score of 8.2/10 (HIGH severity). The EPSS model estimates a 0.33% probability of exploitation in the next 30 days.

How do I fix CVE-2021-33627?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-33627?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST