CVE-2022-33908
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 transactions which are targeted at input buffers used for the SdHostDriver software SMI handler 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 SdHostDriver 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: 05.27.25, kernel 5.3: 05.36.25, kernel 5.4: 05.44.25, kernel 5.5: 05.52.25 https://www.insyde.com/security-pledge/SA-2022050
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 transactions targeting input buffers for the SdHostDriver software SMI (System Management Interrupt) handler can cause SMRAM (System Management RAM) corruption through a Time-Of-Check-Time-Of-Use (TOCTOU) attack. This is a UEFI firmware vulnerability in Insyde's kernel that allows DMA-based memory corruption in the protected SMRAM region used for SMM (System Management Mode).
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>= 5.2, < 5.2.05.27.25>= 5.3, < 5.3.05.36.25>= 5.4, < 5.4.05.44.25>= 5.5, < 5.5.05.52.25CVSS 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 checksWork through these to decide whether this CVE applies to you.
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Identify the UEFI firmware vendorCheck system BIOS/UEFI information using 'dmidecode -s bios-vendor' or manufacturer tools to confirm Insyde is the firmware providerAffected if The system does not use Insyde UEFI firmware - this vulnerability only affects Insyde-based systems
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Determine the Insyde Kernel versionRetrieve the UEFI firmware version string from BIOS setup, 'dmidecode -s bios-version', or the manufacturer's firmware update utility. Extract the kernel version number (e.g., 5.2, 5.3, 5.4, 5.5) and the full version build (e.g., 05.27.xx)Affected if The kernel version falls within any of these ranges: >= 5.2 and < 5.2.05.27.25, >= 5.3 and < 5.3.05.36.25, >= 5.4 and < 5.4.05.44.25, or >= 5.5 and < 5.5.05.52.25
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Verify SdHostDriver is presentExamine the UEFI firmware image using manufacturer tools or hexdump the ROM to search for 'SdHostDriver' string indicators within the firmware binaryAffected if The SdHostDriver module exists in the firmware - the vulnerability requires this driver to be present and loaded as part of the SMM environment
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Confirm SMM is enabledCheck if System Management Mode is active or available by reviewing BIOS settings for SMM features, or by examining /sys/firmware/efi for UEFI systems with SMM configurationAffected if SMM is enabled on the system - the TOCTOU attack targets the SMRAM region used during SMM operations, so SMM must be operational for exploitation
A system is affected if it uses Insyde UEFI firmware with kernel versions 5.2 through 5.2.05.27.24, 5.3 through 5.3.05.36.24, 5.4 through 5.4.05.44.24, or 5.5 through 5.5.05.52.24, and has the SdHostDriver module present with SMM 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 · scoped5.2.05.27.255.3.05.36.255.4.05.44.25
Apply the Insyde firmware updates: kernel 5.2 to version 05.27.25, kernel 5.3 to 05.36.25, kernel 5.4 to 05.44.25, or kernel 5.5 to 05.52.25. Verify systems are running affected firmware versions and deploy the appropriate patch via standard UEFI firmware update processes.
Insyde kernel 5.2: 05.27.25+ / 5.3: 05.36.25+ / 5.4: 05.44.25+ / 5.5: 05.52.25+ (minimum fixed versions per branch)
- 1. Identify the current Insyde kernel/firmware version by checking the UEFI BIOS version on the system (typically displayed during POST or in BIOS setup)
- 2. Determine which kernel branch (5.2, 5.3, 5.4, or 5.5) the current firmware is based on
- 3. Download the appropriate updated UEFI firmware version from Insyde's official support website: kernel 5.2 requires version 05.27.25 or later; kernel 5.3 requires version 05.36.25 or later; kernel 5.4 requires version 05.44.25 or later; kernel 5.5 requires version 05.52.25 or later
- 4. Follow the vendor's standard firmware update procedure (usually via UEFI flash utility, Windows BIOS update tool, or USB-based recovery)
- 5. After firmware update, verify the new version is installed and the system boots normally
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,600.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2022-33908 — 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-2022-33908 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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