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Insydeh2oApplication · Insyde

CVE-2021-42554

HIGH · 8.2 CVSS v3.1 Published 2022-02-03
Fix available
A fix is available. Upgrade to 5.08.42 / 5.16.42 or later.
See remediation →
84/100
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 Insyde InsydeH2O with Kernel 5.0 before 05.08.42, Kernel 5.1 before 05.16.42, Kernel 5.2 before 05.26.42, Kernel 5.3 before 05.35.42, Kernel 5.4 before 05.42.51, and Kernel 5.5 before 05.50.51. An SMM memory corruption vulnerability in FvbServicesRuntimeDxe allows a possible attacker to write fixed or predictable data to SMRAM. Exploiting this issue could lead to escalating privileges to SMM.

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 · high confidence

InsydeH2O UEFI firmware contains an SMM memory corruption vulnerability in the FvbServicesRuntimeDxe driver across multiple kernel versions. An attacker can write fixed or predictable data to SMRAM (System Management RAM), potentially achieving arbitrary code execution at the highest CPU privilege level (SMM), which enables persistent firmware-level compromise.

MitigationUpdate InsydeH2O UEFI firmware to version 05.08.42 or later for Kernel 5.0, 05.16.42 or later for Kernel 5.1, 05.26.42 or later for Kernel 5.2, 05.35.42 or later for Kernel 5.3, 05.42.51 or later for Kernel 5.4, or 05.50.51 or later for Kernel 5.5, per vendor guidance.

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:>= 5.0, < 5.08.42>= 5.1, < 5.16.42>= 5.2, < 5.26.42>= 5.3, < 5.35.42>= 5.4, < 5.42.51>= 5.5, < 5.50.51
Simatic Field Pg M5 FirmwareOperating system
Affected:all versions
Simatic Field Pg M6 FirmwareOperating system
Affected:all versions
Simatic Ipc127e FirmwareOperating system
Affected:all versions
Simatic Ipc227g FirmwareOperating system
Affected:all versions
Simatic Ipc277g FirmwareOperating system
Affected:all versions
Simatic Ipc327g FirmwareOperating system
Affected:all versions
Simatic Ipc377g 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
Low
Privileges
High
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/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 UEFI firmware version
    Run 'dmidecode -s bios-version' or use manufacturer-provided tools (e.g., 'biosinfo' on Windows, 'fwupdtool get-vars' or UEFI shell 'dmidecode') to retrieve the installed UEFI firmware version
    Affected if The displayed version falls within the affected ranges: for Kernel 5.0: < 05.08.42; Kernel 5.1: < 05.16.42; Kernel 5.2: < 05.26.42; Kernel 5.3: < 05.35.42; Kernel 5.4: < 05.42.51; Kernel 5.5: < 05.50.51, or is an unpatched Siemens device firmware version
  2. Determine InsydeH2O kernel version
    Use UEFI shell 'dmidecode -t 0' or check manufacturer documentation; some systems expose the firmware kernel version via 'fwupdtool get-vars' or by reading the UEFI setup screen for the firmware revision string which may contain a kernel identifier
    Affected if The kernel version shown is 5.0, 5.1, 5.2, 5.3, 5.4, or 5.5 and the corresponding version number is below the fixed versions listed in the CVE
  3. Verify FvbServicesRuntimeDxe driver presence
    From UEFI shell, run 'drivers' or use 'efimgr' tool to list loaded UEFI drivers; look for FvbServicesRuntimeDxe in the driver list
    Affected if The FvbServicesRuntimeDxe driver is listed as loaded or present in the firmware image
  4. Identify Siemens device model and firmware version
    For Siemens Simatic devices (Field Pg M5/M6, Ipc127e, Ipc227g, Ipc277g, Ipc327g, Ipc377g), use the device's web interface, SIMATIC IPC Manager, or manufacturer firmware update tool to retrieve the installed firmware version
    Affected if The device is any of the listed Siemens models running any firmware version, as all versions of these products are affected according to the CVE

You are affected if your InsydeH2O firmware kernel version falls within the specified vulnerable ranges and is below the fixed versions, or if your device is one of the listed Siemens models running any firmware version.

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 5.08.42 / 5.16.42 / 5.26.42 or later
Fixed in 5.08.425.16.425.26.42
Interim mitigation

Update InsydeH2O UEFI firmware to version 05.08.42 or later for Kernel 5.0, 05.16.42 or later for Kernel 5.1, 05.26.42 or later for Kernel 5.2, 05.35.42 or later for Kernel 5.3, 05.42.51 or later for Kernel 5.4, or 05.50.51 or later for Kernel 5.5, per vendor guidance.

Recommended fix High confidence

InsydeH2O Kernel 5.0 to 05.08.42+; Kernel 5.1 to 05.16.42+; Kernel 5.2 to 05.26.42+; Kernel 5.3 to 05.35.42+; Kernel 5.4 to 05.42.51+; Kernel 5.5 to 05.50.51+ | Simatic products: Contact Siemens for specific patched firmware

  1. 1. Identify the InsydeH2O kernel version running on the affected device by checking the UEFI/BIOS firmware version information.
  2. 2. For InsydeH2O devices: Upgrade to the appropriate fixed kernel version: Kernel 5.0 to 05.08.42 or later; Kernel 5.1 to 05.16.42 or later; Kernel 5.2 to 05.26.42 or later; Kernel 5.3 to 05.35.42 or later; Kernel 5.4 to 05.42.51 or later; Kernel 5.5 to 05.50.51 or later.
  3. 3. Obtain the firmware update from the device manufacturer (OEM) - InsydeH2O is a framework used by multiple OEMs, so obtain the update through the OEM's support channels.
  4. 4. For Siemens Simatic products (Field Pg M5/M6, IPC127e, IPC227g, IPC277g, IPC327g, IPC377g): Contact Siemens customer support or visit the Siemens industrial security portal to obtain patched firmware. These products list all versions as affected, indicating specific patch availability must be confirmed with Siemens.
  5. 5. Apply the firmware update following the OEM's documented firmware flashing procedure, ensuring power stability during the update process.
  6. 6. Verify the firmware version after update to confirm the patch has been successfully applied.
Caveat Firmware updates in UEFI/BIOS can brick devices if interrupted; follow OEM flashing procedures exactly and ensure stable power

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

Fix this in Insydeh2o Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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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-2021-42554 in production — separate from our analysis above.

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