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Insydeh2oApplication · Insyde

CVE-2021-33625

HIGH · 7.5 CVSS v3.1 Published 2022-02-03
Fix available
A fix is available. Upgrade to 5.16.23 / 5.26.23 or later.
See remediation →
77/100
Remediation priority · High
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
An issue was discovered in Kernel 5.x in Insyde InsydeH2O, affecting HddPassword. 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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

A vulnerability in Insyde InsydeH2O kernel 5.x allows Software SMI services using the Communicate() function of EFI_SMM_COMMUNICATION_PROTOCOL to operate without validating buffer addresses. This enables an attacker to access SMRAM, MMIO, or OS kernel addresses, potentially leading to arbitrary code execution in SMM with the highest privilege level.

MitigationApply vendor-supplied firmware updates from Insyde. Until an update is available, consider restricting physical access to affected systems and monitoring for unusual SMM activity.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Insydeh2oApplication
Affected:>= 5.1, < 5.16.23>= 5.2, < 5.26.23>= 5.3, < 5.35.23>= 5.4, < 5.43.22>= 5.5, < 5.51.22
Fas\/aff BiosOperating system
Affected:all versions
Ruggedcom Ape1808 FirmwareOperating system
Affected:all versions
Simatic Field Pg M5 FirmwareOperating system
Affected:all versions
Simatic Ipc127e FirmwareOperating system
Affected:all versions
Simatic Itp1000 FirmwareOperating system
Affected:all versions
Simatic Ipc277g FirmwareOperating system
Affected:all versions
Simatic Ipc227g FirmwareOperating system
Affected:all versions

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
High
Privileges
High
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify the system BIOS firmware version
    Use system information tools such as 'dmidecode -s bios-version' on Linux, 'wmic bios get version' on Windows, or check the UEFI/BIOS setup utility under the Main or Information tab to locate the BIOS version string.
    Affected if The version cannot be determined or the system uses InsydeH2O firmware and the version falls within any of the affected ranges: >= 5.1 to < 5.16.23, >= 5.2 to < 5.26.23, >= 5.3 to < 5.35.23, >= 5.4 to < 5.43.22, or >= 5.5 to < 5.51.22.
  2. Verify the BIOS vendor is InsydeH2O
    Execute 'dmidecode -s bios-vendor' on Linux or 'wmic bios get manufacturer' on Windows to retrieve the BIOS vendor information.
    Affected if The BIOS vendor is Insyde and the version is in any of the affected ranges listed above.
  3. Check if the system is a NetApp FAS/AFF storage array
    Identify the system model using 'lscpu' or 'dmidecode -s system-product-name' on Linux, or check the physical product labeling. NetApp FAS/AFF systems typically run OnTap OS but contain InsydeH2O-based BIOS firmware.
    Affected if The system is a NetApp FAS or AFF appliance running any BIOS version since these are listed as affected for all versions.
  4. Identify Siemens device model and firmware version
    Check the device labeling or access the device's firmware/BIOS settings during boot. For the listed Siemens products (Ruggedcom Ape1808, Simatic Field Pg M5, Simatic Ipc127e, Simatic Itp1000, Simatic Ipc277g, Simatic Ipc227g), retrieve the BIOS or firmware version from the device firmware update utility or system information.
    Affected if The device is any of the listed Siemens models running their current firmware since these are affected for all versions.
  5. Inspect for SMM communication configuration
    Review the UEFI/BIOS setup configuration screens for any Software SMI or SMM-related settings. On InsydeH2O systems, this is typically found under 'Advanced' or 'Security' settings. Check if 'SMM Security' or similar protections are configurable.
    Affected if The system uses InsydeH2O firmware in an affected version and lacks SMM buffer address validation, which may be indicated by missing or disabled SMM security protections in the BIOS configuration.

A system is affected if it runs InsydeH2O BIOS firmware with a version matching any of the vulnerable ranges, or if it is a NetApp FAS/AFF system or any of the listed Siemens devices regardless of version, as all of these contain the unpatched InsydeH2O kernel code with the vulnerable EFI_SMM_COMMUNICATION_PROTOCOL implementation.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 5.16.23 / 5.26.23 / 5.35.23 or later
Fixed in 5.16.235.26.235.35.23
Interim mitigation

Apply vendor-supplied firmware updates from Insyde. Until an update is available, consider restricting physical access to affected systems and monitoring for unusual SMM activity.

Recommended fix High confidence

InsydeH2O: 5.16.23 or later (5.1.x branch), 5.26.23 or later (5.2.x branch), 5.35.23 or later (5.3.x branch), 5.43.22 or later (5.4.x branch); Siemens/Ruggedcom: contact vendor for fixed firmware

  1. For InsydeH2O based systems: Identify the specific InsydeH2O version currently installed (typically viewable during POST or via BIOS setup utility information page)
  2. Determine which version branch applies to your system: 5.1.x series should upgrade to >= 5.16.23; 5.2.x series should upgrade to >= 5.26.23; 5.3.x series should upgrade to >= 5.35.23; 5.4.x series should upgrade to >= 5.43.22
  3. Obtain the BIOS/UEFI firmware update from the original equipment manufacturer (OEM) that includes the fixed InsydeH2O version
  4. Apply the BIOS update following the OEM's documented firmware update procedure, typically via a USB flash drive or through the OEM's management tools
  5. For Siemens Simatic devices (Ipc127e, Ipc227g, Ipc277g, Ipc1000, Field Pg M5) and Ruggedcom Ape1808: Contact Siemens product security for firmware updates addressing CVE-2021-33625
  6. For FSF/Aff Bios: Contact the vendor for patched firmware
Caveat BIOS firmware updates carry risk of rendering the system unbootable if interrupted; ensure stable power and follow OEM update procedures exactly; some OEM updates may reset BIOS settings to defaults

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Insydeh2o Scoped from the published advisory
  • Consultation6.0 h
  • Implementation16.0 h
  • Testing12.0 h
  • Review / QA8.0 h
42.0 hours of engineering $7,320
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-33625 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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