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Insydeh2oApplication · Insyde

CVE-2021-41841

HIGH · 8.2 CVSS v3.1 Published 2022-02-03
Fix available
A fix is available. Upgrade to 5.08.29 / 5.16.29 or later.
See remediation →
84/100
Remediation priority · High
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
An issue was discovered in AhciBusDxe in the kernel 5.0 through 5.5 in Insyde InsydeH2O. There is an SMM callout that allows an attacker to access the System Management Mode and execute arbitrary code. This occurs because of Inclusion of Functionality from an Untrusted Control Sphere.

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

Vulnerability in AhciBusDxe UEFI driver in InsydeH2O firmware versions 5.0-5.5 allows an attacker to execute arbitrary code in System Management Mode (SMM) through an SMM callout. The root cause is inclusion of untrusted functionality from an external control sphere into the SMM-protected code path.

MitigationApply vendor firmware update from Insyde for the affected InsydeH2O versions 5.0-5.5. No software workaround exists for this SMM vulnerability; firmware patching is the only remediation.

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
Insydeh2oApplication
Affected:>= 5.0, < 5.08.29>= 5.1, < 5.16.29>= 5.2, < 5.26.29>= 5.3, < 5.35.29>= 5.4, < 5.43.29>= 5.5, < 5.51.29

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
Low
Privileges
High
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/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 InsydeH2O firmware version
    Run 'dmidecode -s bios-version' or check /sys/class/dmi/id/bios_version on Linux, or use the vendor's firmware tool or UEFI setup utility to view BIOS/firmware version
    Affected if The version falls within any of these ranges: >= 5.0 and < 5.08.29; >= 5.1 and < 5.16.29; >= 5.2 and < 5.26.29; >= 5.3 and < 5.35.29; >= 5.4 and < 5.43.29; >= 5.5 and < 5.51.29
  2. Confirm InsydeH2O as the firmware vendor
    Run 'dmidecode -s bios-vendor' or check /sys/class/dmi/id/bios_vendor to verify the system uses InsydeH2O firmware
    Affected if The vendor is Insyde and the version matches the affected ranges above
  3. Check for AhciBusDxe driver presence
    Examine UEFI firmware image or use UEFI tool 'efi-explorer' or 'uefi-firmware-parser' to extract and list drivers in the firmware, looking for AhciBusDxe driver
    Affected if The AhciBusDxe driver exists in the firmware build and the firmware version is in the affected ranges

A system is affected if it runs InsydeH2O firmware versions 5.0 through 5.51.28 (specific to each branch) with the vulnerable AhciBusDxe driver present in the UEFI firmware.

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 5.08.29 / 5.16.29 / 5.26.29 or later
Fixed in 5.08.295.16.295.26.29
Interim mitigation

Apply vendor firmware update from Insyde for the affected InsydeH2O versions 5.0-5.5. No software workaround exists for this SMM vulnerability; firmware patching is the only remediation.

Recommended fix High confidence

InsydeH2O kernel version 5.08.29 or later (5.0 branch); 5.16.29 or later (5.1 branch); 5.26.29 or later (5.2 branch); 5.35.29 or later (5.3 branch)

  1. 1. Identify the current InsydeH2O kernel version by checking the UEFI firmware version on the affected system
  2. 2. Determine which version branch (5.0, 5.1, 5.2, or 5.3) the current firmware is based on
  3. 3. Contact the system hardware vendor (OEM) to obtain the appropriate InsydeH2O firmware update containing the security fix
  4. 4. Apply the vendor-provided firmware update following the vendor's documented update procedure
  5. 5. Verify the firmware has been successfully updated to version 5.08.29 (for 5.0 branch), 5.16.29 (for 5.1 branch), 5.26.29 (for 5.2 branch), or 5.35.29 (for 5.3 branch) or higher
Caveat Firmware updates carry inherent risks and should be tested in a controlled environment before production deployment; ensure uninterrupted power during the update process

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

Fix this in Insydeh2o Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing6.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,980
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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-2021-41841 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
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data