CVE-2023-39283
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 SMM memory corruption vulnerability in the SMM driver (SMRAM write) in CsmInt10HookSmm in Insyde InsydeH2O with kernel 5.0 through 5.5 allows attackers to send arbitrary data to SMM which could lead to privilege escalation.
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 System Management Mode (SMM) memory corruption vulnerability in the CsmInt10HookSmm SMM driver within InsydeH2O firmware kernel versions 5.0 through 5.5. The flaw allows attackers to write arbitrary data to SMRAM (SMM memory region), potentially executing code in the highly privileged SMM environment and achieving privilege escalation from OS level to SMM.
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>= 5.0, <= 5.5= 5.5.05.53.22= 5.6= 5.6.05.60.22CVSS 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
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/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 InsydeH2O firmware versionRead the UEFI/BIOS firmware version from system information utilities such as dmidecode (dmidecode -s bios-version), UEFI shell version command, or check the BIOS setup menu under 'Main' or 'BIOS Information'Affected if The displayed version falls within 5.0 to 5.5 inclusive, or matches exactly 5.5.05.53.22, 5.6, or 5.6.05.60.22
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Confirm CSM module statusEnter UEFI/BIOS setup and locate the Compatibility Support Module (CSM) or 'Boot' configuration settings. Verify whether CSM is enabled or disabledAffected if CSM is enabled - the vulnerable CsmInt10HookSmm driver loads when CSM is active for legacy BIOS video compatibility
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Check SMRAM accessibilityInspect SMRAM region status using OS-level tools such as 'msr' tools, or by checking /proc/boot_mode or accessing via UEFI shell with 'mm -a' for memory map. Look for any indication that SMRAM is not properly locked or is exposed to OSAffected if SMRAM is unlocked or accessible from OS level, indicating the conditions for potential exploitation of SMM memory corruption
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Verify SMM driver presenceUse UEFI shell to list loaded SMM drivers, or on Linux check /sys/firmware/efi/smm_commmand for SMM communication interfaces. Look for a driver with 'CsmInt10Hook' in its nameAffected if The CsmInt10HookSmm driver is present and loaded in the SMM environment
A system is affected if it runs InsydeH2O firmware version 5.0-5.5 (or the specific versions listed) with CSM enabled and has the vulnerable CsmInt10HookSmm driver loaded, allowing potential SMM privilege escalation from OS level.
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.
From vendor dataApply vendor-supplied firmware updates from Insyde that address this vulnerability. Prior to update, restrict local physical access and ensure only trusted code can interact with low-level system management interfaces.
- Consultation2.0 h
- Implementation4.0 h
- Testing6.0 h
- Review / QA3.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-39283 — 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-2023-39283 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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