CVE-2022-33986
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 · uneditedDMA attacks on the parameter buffer used by the VariableRuntimeDxe software SMI handler could lead to a TOCTOU attack. DMA attacks on the parameter buffer used by the software SMI handler used by the driver VariableRuntimeDxe could lead to a TOCTOU attack on the SMI handler and lead to corruption of SMRAM. This issue was discovered by Insyde engineering during a security review. This issue is fixed in Kernel 5.4: 05.44.23 and Kernel 5.5: 05.52.23. CWE-367 CWE-367 Report at: https://www.insyde.com/security-pledge/SA-2022056
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 confidenceDMA attacks on the parameter buffer used by the VariableRuntimeDxe software SMI handler create a TOCTOU (Time-of-Check to Time-of-Use) race condition. An attacker with DMA capability could manipulate the parameter buffer between the time the handler checks the buffer contents and when it uses those values, potentially corrupting SMRAM (System Management RAM). This is a firmware-level vulnerability in Insyde's UEFI implementation.
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>= 5.4, < 5.4.05.44.23>= 5.5, < 5.5.05.52.23CVSS 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 checksWork through these to decide whether this CVE applies to you.
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Identify the system firmware/BIOS versionOn the target system, retrieve the UEFI/BIOS version from the firmware setup utility or via system information tools (e.g., dmidecode -s bios-version on Linux, or msinfo32 on Windows). Record the full version string.Affected if The firmware version maps to an Insyde Kernel version between 5.4 and 5.4.05.44.22, or between 5.5 and 5.5.05.52.22.
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Determine the Insyde Kernel version from firmwareConsult the hardware vendor's documentation to map the BIOS/firmware version to the corresponding Insyde Kernel version. Insyde Kernel version information may also be visible in firmware update logs or via UEFI shell (using 'dmidecode' or 'efibootmgr -v' on Linux, or system information utilities on Windows).Affected if The Insyde Kernel version falls within the affected ranges: >= 5.4 and < 5.4.05.44.23, or >= 5.5 and < 5.5.05.52.23.
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Verify if VariableRuntimeDxe is presentCheck the UEFI firmware modules loaded on the system. This can be done via UEFI shell using 'dmem -t DRIVER' or by examining the firmware image with tools like uefi-firmware-parser or innoextract-uefi. Look for the VariableRuntimeDxe driver.Affected if The VariableRuntimeDxe driver is present and loaded at runtime, which is required for the vulnerable code path to be exercised.
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Check if IOMMU/DMA protection is enabledAccess the UEFI/BIOS settings and verify whether IOMMU (also called Intel VT-d or AMD-Vi) is enabled. On Linux, this can be checked via 'dmesg | grep -i iommu' or by checking /sys/class/iommu/. On Windows, check Device Manager for Intel VT-d or look in BIOS settings.Affected if IOMMU is disabled or not available on the system, leaving the parameter buffer vulnerable to DMA manipulation.
A system is affected if it runs Insyde Kernel firmware versions 5.4.x below 5.4.05.44.23 or 5.5.x below 5.5.05.52.23, with the VariableRuntimeDxe driver loaded and without IOMMU DMA protection enabled.
Generated from the published advisory. Verify against your own configuration.
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 · scoped5.4.05.44.235.5.05.52.23
Apply the vendor-supplied firmware patches: Kernel 5.4 version 05.44.23 or Kernel 5.5 version 05.52.23. This is a firmware-level fix requiring a BIOS/UEFI update from the hardware vendor.
Kernel 5.4: 05.44.23 or later; Kernel 5.5: 05.52.23 or later
- 1. Identify the current Insyde Kernel version (5.4.x or 5.5.x) of the affected system
- 2. For systems running Kernel 5.4.x: Upgrade to Kernel version 05.44.23 or later
- 3. For systems running Kernel 5.5.x: Upgrade to Kernel version 05.52.23 or later
- 4. Apply the firmware update through the vendor's standard BIOS/UEFI firmware update process
- 5. Verify the updated Kernel version after applying the fix
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation1.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2022-33986 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2022-33986 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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