What’s Vulnerable › Vulnerabilities

CVE-2021-33627

• Severity: high (CVSS 8.2 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2022-02-03 · updated 2026-08-11
• Weakness: CWE-119

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.

Affected products

• Insydeh2O: from 5.0 before 5.08.29; from 5.1 before 5.16.29; from 5.2 before 5.26.29; from 5.3 before 5.35.29 — fixed in 5.08.29, 5.16.29, 5.26.29, 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

How to fix

Upgrade to a fixed version: Insydeh2O 5.08.29, 5.16.29, 5.26.29, 5.35.29. Check the vendor advisory for mitigations.

References

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

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