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KernelApplication · Insyde

CVE-2022-33905

HIGH · 7.0 CVSS v3.1 Published 2022-11-15
Fix available
A fix is available. Upgrade to 5.2.05.27.23 / 5.3.05.36.23 or later.
See remediation →
72/100
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
DMA transactions which are targeted at input buffers used for the AhciBusDxe software SMI handler could cause SMRAM corruption (a TOCTOU attack). DMA transactions which are targeted at input buffers used for the software SMI handler used by the AhciBusDxe driver could cause SMRAM corruption through a TOCTOU attack. This issue was discovered by Insyde engineering based on the general description provided by Intel's iSTARE group, Fixed in kernel 5.2: 05.27.23, kernel 5.3: 05.36.23, kernel 5.4: 05.44.23, kernel 5.5: 05.52.23 https://www.insyde.com/security-pledge/SA-2022047

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

A TOCTOU (Time-of-Check to Time-of-Use) vulnerability in the AhciBusDxe driver's software SMI handler allows DMA transactions to corrupt SMRAM (System Management RAM). Attackers can exploit the race condition between checking input buffer permissions and using those buffers to inject malicious code into SMM (System Management Mode).

MitigationApply Insyde firmware patches (kernel 5.2: 05.27.23, 5.3: 05.36.23, 5.4: 05.44.23, 5.5: 05.52.23 or later). Disable DMA for untrusted devices if possible and ensure SMRAM is not exposed to external DMA-capable devices.

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, < 5.2.05.27.23>= 5.3, < 5.3.05.36.23>= 5.4, < 5.4.05.44.23>= 5.5, < 5.5.05.52.23

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
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:H/PR:L/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 the Insyde Kernel firmware version
    Check the UEFI/BIOS firmware version reported by `dmidecode -s bios-version` or through the BIOS setup menu under 'BIOS Information' or 'Firmware Version'. Compare the kernel version number to the affected ranges: 5.2.x (< 5.2.05.27.23), 5.3.x (< 5.3.05.36.23), 5.4.x (< 5.4.05.44.23), 5.5.x (< 5.5.05.52.23).
    Affected if The installed firmware kernel version falls within any of the affected version ranges.
  2. Verify the AhciBusDxe driver is present in the firmware
    Inspect the UEFI firmware image using tools such as `uefi-firmware-parser`, `binwalk`, or Insyde's firmware update tools. Look for the AhciBusDxe driver module (typically named AhciBusDxe.efi or similar) within the firmware volume.
    Affected if The AhciBusDxe driver is present in the firmware build.
  3. Confirm AHCI SATA controller is enabled
    Check system configuration via `lspci | grep -i ahci` or through BIOS setup to verify that an AHCI SATA controller is active. The vulnerability only affects systems where AHCI mode is enabled.
    Affected if AHCI mode is enabled for SATA controllers in the system.
  4. Check DMA exposure of SATA controller
    Examine PCIe device assignment and DMA capabilities using `lspci -v` or IOMMU settings via `dmesg | grep -i iommu`. Determine if the SATA controller has direct memory access without IOMMU protection.
    Affected if The SATA controller has unrestricted DMA access and IOMMU is disabled or not filtering DMA transactions.

A system is affected if it runs an Insyde Kernel firmware version within the affected ranges AND has the AhciBusDxe driver with AHCI controller enabled, allowing the TOCTOU race condition in the SMI handler to potentially corrupt SMRAM.

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 5.2.05.27.23 / 5.3.05.36.23 / 5.4.05.44.23 or later
Fixed in 5.2.05.27.235.3.05.36.235.4.05.44.23
Interim mitigation

Apply Insyde firmware patches (kernel 5.2: 05.27.23, 5.3: 05.36.23, 5.4: 05.44.23, 5.5: 05.52.23 or later). Disable DMA for untrusted devices if possible and ensure SMRAM is not exposed to external DMA-capable devices.

Recommended fix High confidence

Kernel 5.2: 05.27.23 or later; Kernel 5.3: 05.36.23 or later; Kernel 5.4: 05.44.23 or later; Kernel 5.5: 05.52.23 or later

  1. 1. Identify the current Insyde kernel version installed on the affected system
  2. 2. Determine which kernel branch (5.2, 5.3, 5.4, or 5.5) the system is running
  3. 3. Obtain the firmware update containing the fixed kernel version for that branch from Insyde
  4. 4. Apply the firmware update following the vendor's standard update procedure
  5. 5. Verify the update was applied successfully by confirming the new kernel version
Caveat Firmware updates carry inherent risks; test in controlled environment before production deployment

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

Fix this in Kernel Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,130
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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-2022-33905 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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  • No spam, self-promotion, credentials, or personal data