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Insydeh2oApplication · Insyde

CVE-2021-43323

HIGH · 8.2 CVSS v3.1 Published 2022-02-03
Fix available
A fix is available. Upgrade to 5.08.45 / 5.16.45 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 UsbCoreDxe in Insyde InsydeH2O with kernel 5.5 before 05.51.45, 5.4 before 05.43.45, 5.3 before 05.35.45, 5.2 before 05.26.45, 5.1 before 05.16.45, and 5.0 before 05.08.45. An SMM callout vulnerability allows an attacker to hijack execution flow of code running in System Management Mode. Exploiting this issue could lead to escalating privileges to SMM.

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

This is an SMM (System Management Mode) callout vulnerability in the UsbCoreDxe driver of InsydeH2O UEFI firmware. The flaw allows an attacker to hijack the execution flow of code running in SMM, enabling privilege escalation to the highest privilege level in the system. Multiple kernel versions (5.0-5.5) are affected with specific patched version requirements.

MitigationApply the InsydeH2O firmware update to the specified patched versions (05.51.45 for kernel 5.5, 05.43.45 for 5.4, 05.35.45 for 5.3, 05.26.45 for 5.2, 05.16.45 for 5.1, 05.08.45 for 5.0) through the vendor's BIOS update mechanism.

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:>= 5.1, < 5.16.45>= 5.2, < 5.26.45>= 5.3, < 5.33.45>= 5.0, < 5.08.45>= 5.4, < 5.43.45>= 5.5, < 5.51.45

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 the InsydeH2O firmware version
    Run `dmidecode -s bios-version` or check system firmware/BIOS information through the operating system or BIOS setup menu. Look for a version string in the format XX.XX.XX (e.g., 05.08.45, 05.16.45, etc.)
    Affected if The version is lower than any of the patched versions: 05.08.45 (kernel 5.0), 05.16.45 (kernel 5.1), 05.26.45 (kernel 5.2), 05.35.45 (kernel 5.3), 05.43.45 (kernel 5.4), 05.51.45 (kernel 5.5)
  2. Determine the InsydeH2O kernel version
    The InsydeH2O kernel version is embedded in the firmware version number. The first two digits after the leading zero (or the first two digits) indicate the kernel: 05.0X.XX indicates kernel 5.0, 05.1X.XX indicates kernel 5.1, and so on up to 05.5X.XX for kernel 5.5
    Affected if The kernel version falls within 5.0 through 5.5 and the full version is below the corresponding patch threshold for that kernel
  3. Confirm the UsbCoreDxe driver presence
    Inspect the UEFI firmware image or use system tools that enumerate loaded UEFI drivers. On Linux, tools like `uefivars` or reading from `/sys/firmware/efi` may provide driver information. The driver is typically present in the UEFI firmware ROM
    Affected if The UsbCoreDxe driver is present in the system firmware (this is standard on InsydeH2O systems with USB support)
  4. Cross-reference version against affected ranges
    Compare your identified kernel version and firmware version against these affected ranges: kernel 5.0 < 05.08.45, kernel 5.1 < 05.16.45, kernel 5.2 < 05.26.45, kernel 5.3 < 05.33.45, kernel 5.4 < 05.43.45, kernel 5.5 < 05.51.45
    Affected if Your firmware version is within any of these vulnerable ranges

A system is affected if it runs InsydeH2O UEFI firmware with a kernel version between 5.0 and 5.5 and a firmware version below the corresponding patched threshold for that kernel.

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 5.08.45 / 5.16.45 / 5.26.45 or later
Fixed in 5.08.455.16.455.26.45
Interim mitigation

Apply the InsydeH2O firmware update to the specified patched versions (05.51.45 for kernel 5.5, 05.43.45 for 5.4, 05.35.45 for 5.3, 05.26.45 for 5.2, 05.16.45 for 5.1, 05.08.45 for 5.0) through the vendor's BIOS update mechanism.

Recommended fix High confidence

InsydeH2O kernel 5.0 to version 05.08.45 or later; kernel 5.1 to 05.16.45 or later; kernel 5.2 to 05.26.45 or later; kernel 5.3 to 05.35.45 or later; kernel 5.4 to 05.43.45 or later; kernel 5.5 to 05.51.45 or later

  1. 1. Identify the current InsydeH2O kernel version installed on the affected system by checking the UEFI/BIOS firmware version information.
  2. 2. Determine which kernel branch (5.0, 5.1, 5.2, 5.3, 5.4, or 5.5) the current version belongs to based on the version numbering pattern.
  3. 3. Obtain the fixed firmware version from the system manufacturer (OEM) that includes the InsydeH2O update to the specific fixed release for the applicable branch.
  4. 4. Apply the firmware update from the OEM, ensuring the update includes the UsbCoreDxe fix for CVE-2021-43323.
Caveat Firmware updates carry inherent risks and should be tested in a controlled environment before production deployment; verify OEM support and ensure the update is applicable to the specific hardware model

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

Fix this in Insydeh2o Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,120
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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-2021-43323 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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