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KernelApplication · Insyde

CVE-2022-31243

MEDIUM · 6.4 CVSS v3.1 Published 2022-11-15
Fix available
A fix is available. Upgrade to 5.2.05.27.21 / 5.3.05.36.21 or later.
See remediation →
66/100
Remediation priority · Elevated
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
Update description and links DMA transactions which are targeted at input buffers used for the software SMI handler used by the FvbServicesRuntimeDxe driver could cause SMRAM corruption through a TOCTOU attack.. "DMA transactions which are targeted at input buffers used for the software SMI handler used by the FvbServicesRuntimeDxe driver could cause SMRAM corruption. This issue was discovered by Insyde engineering based on the general description provided by Intel's iSTARE group. Fixed in Kernel 5.2: 05.27.21. Kernel 5.3: 05.36.21. Kernel 5.4: 05.44.21. Kernel 5.5: 05.52.21 https://www.insyde.com/security-pledge/SA-2022044

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

DMA transactions targeting input buffers for the software SMI handler in Insyde's FvbServicesRuntimeDxe driver can corrupt SMRAM via a TOCTOU (Time-of-Check-to-Time-of-Use) race condition. SMRAM houses the System Management Mode (SMM) code, so corruption could allow execution of malicious code at the highest CPU privilege level.

MitigationUpdate system UEFI firmware to the patched Kernel versions (5.2: 05.27.21, 5.3: 05.36.21, 5.4: 05.44.21, or 5.5: 05.52.21 or later) as provided by the Insyde OEM/ODM vendor.

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
KernelApplication
Affected:>= 5.2, < 5.2.05.27.21>= 5.3, < 5.3.05.36.21>= 5.4, < 5.4.05.44.21>= 5.5, < 5.5.05.52.21

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
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/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 vendor
    Run 'dmidecode -s bios-vendor' or check system information to determine if the BIOS is from Insyde (or InsydeH2O)
    Affected if Firmware vendor is not Insyde (the vulnerability only affects Insyde-based UEFI firmware)
  2. Check Insyde Kernel version
    Run 'dmidecode -s bios-version' or use the OEM-provided tool to retrieve the firmware/UEFI version string (often contains the Kernel version like 5.2, 5.3, etc.)
    Affected if The version string cannot be retrieved or does not match Insyde versioning pattern
  3. Compare against affected version ranges
    Parse the retrieved firmware version and identify the Kernel branch (5.2, 5.3, 5.4, or 5.5) and full version number (e.g., 05.27.21), then compare against: 5.2 < 05.27.21, 5.3 < 05.36.21, 5.4 < 05.44.21, 5.5 < 05.52.21
    Affected if The installed Kernel version falls within any of the affected ranges (5.2 through 5.2.x before 05.27.21, 5.3 through 5.3.x before 05.36.21, 5.4 through 5.4.x before 05.44.21, or 5.5 through 5.5.x before 05.52.21)
  4. Check for FvbServicesRuntimeDxe driver
    Extract and inspect the UEFI firmware image (using tools like uefi-firmware-parser or AMI's MMTool) for the presence of the FvbServicesRuntimeDxe driver
    Affected if The driver is present in the firmware and the Kernel version is within the affected ranges (the driver must be loaded for the flaw to be exploitable)

A system is affected if it uses Insyde-based UEFI firmware with Kernel versions 5.2.x < 05.27.21, 5.3.x < 05.36.21, 5.4.x < 05.44.21, or 5.5.x < 05.52.21, and the FvbServicesRuntimeDxe driver is present and active.

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 5.2.05.27.21 / 5.3.05.36.21 / 5.4.05.44.21 or later
Fixed in 5.2.05.27.215.3.05.36.215.4.05.44.21
Interim mitigation

Update system UEFI firmware to the patched Kernel versions (5.2: 05.27.21, 5.3: 05.36.21, 5.4: 05.44.21, or 5.5: 05.52.21 or later) as provided by the Insyde OEM/ODM vendor.

Recommended fix High confidence

Upgrade to Insyde Kernel 5.2.05.27.21+, 5.3.05.36.21+, 5.4.05.44.21+, or 5.5.05.52.21+ (depending on your current branch)

  1. 1. Identify the current Insyde Kernel version (5.2.x, 5.3.x, 5.4.x, or 5.5.x) by checking the system firmware or bootloader configuration
  2. 2. For Kernel 5.2.x: upgrade to version 5.2.05.27.21 or later
  3. 3. For Kernel 5.3.x: upgrade to version 5.3.05.36.21 or later
  4. 4. For Kernel 5.4.x: upgrade to version 5.4.05.44.21 or later
  5. 5. For Kernel 5.5.x: upgrade to version 5.5.05.52.21 or later
  6. 6. Apply the firmware update through the vendor's standard BIOS/UEFI update process
  7. 7. Verify the update was successful by checking the kernel version after reboot
Caveat Firmware updates carry inherent risks; ensure proper backup and power stability during the update process

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

Fix this in Kernel Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
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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-2022-31243 in production — separate from our analysis above.

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  • Version or environment caveats, and links to real fixes
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