CVE-2023-39284
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 · uneditedAn issue was discovered in IhisiServicesSmm in Insyde InsydeH2O with kernel 5.0 through 5.5. There are arbitrary calls to SetVariable with unsanitized arguments in the SMI handler.
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 confidenceThis is a vulnerability in InsydeH2O UEFI firmware (versions 5.0-5.5) within the IhisiServicesSmm SMI handler. The flaw allows arbitrary calls to the UEFI SetVariable runtime service with unsanitized arguments, potentially enabling an attacker with local access to modify UEFI variables (including boot configuration or secure boot settings) from 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, < 5.2.05.28.33>= 5.3, < 5.3.05.37.33>= 5.4, < 5.4.05.45.33>= 5.5, < 5.5.05.53.33>= 5.6, < 5.6.05.60.33CVSS 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
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
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 vendor and versionBoot into the UEFI/BIOS setup menu and look for the firmware version information, typically found under 'Main', 'System Information', or 'BIOS Version'. On Linux, you can also try: 'sudo dmidecode -s bios-version' or 'sudo fwupdmgr get-devices' to retrieve firmware details.Affected if The firmware is made by Insyde (InsydeH2O) and the version falls within any of these ranges: 5.2.x before 5.2.05.28.33, 5.3.x before 5.3.05.37.33, 5.4.x before 5.4.05.45.33, 5.5.x before 5.5.05.53.33, or 5.6.x before 5.6.05.60.33.
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Confirm the IhisiServicesSmm SMI handler is presentThis requires analyzing the UEFI firmware image directly. Extract the firmware ROM using tools like UEFI firmware tools (uefi-firmware-parser) or flashrom, then search for the string 'IhisiServicesSmm' within the firmware binary.Affected if The string 'IhisiServicesSmm' is found in the firmware image, indicating the vulnerable SMI handler is present on the system.
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Verify SetVariable runtime service access from SMMThis is a deeper technical check requiring analysis of the SMI handler code. Disassemble or inspect the IhisiServicesSmm handler to confirm it calls the UEFI SetVariable service without proper input validation on the parameters.Affected if The SMI handler directly invokes the SetVariable runtime service with unsanitized input parameters, allowing arbitrary UEFI variable modification.
If the system uses InsydeH2O firmware at a version within the affected ranges listed above and contains the IhisiServicesSmm component, the environment is vulnerable to arbitrary UEFI variable modification from SMM.
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 · scoped5.2.05.28.335.3.05.37.335.4.05.45.33
Apply the vendor-supplied firmware update from Insyde that patches the SMI handler vulnerability. Until then, restrict physical access and monitor for signs of firmware tampering, as exploitation requires local or physical access.
InsydeH2O 5.2.05.28.33 (for 5.2.x branch), 5.3.05.37.33 (for 5.3.x branch), 5.4.05.45.33 (for 5.4.x branch), or 5.5.05.53.33 (for 5.5.x branch)
- Verify the current InsydeH2O firmware version installed on the affected system through the UEFI BIOS setup or system information utility
- Obtain the appropriate InsydeH2O firmware update from the system manufacturer's support website that includes the fixed version for your specific branch
- Apply the firmware update following the manufacturer's recommended process, which typically involves: a) downloading the BIOS update file, b) running the update utility or placing the file on a USB drive, c) rebooting the system and initiating the BIOS update process from within the UEFI setup or through a bootable media
- After the firmware update completes, verify that the new version matches or exceeds the fixed version for your branch (5.2.05.28.33, 5.3.05.37.33, 5.4.05.45.33, or 5.5.05.53.33)
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation2.0 h
- Testing8.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-39284 — 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-2023-39284 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
- No weaponised exploit code, or anything meant to cause harm
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