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CVE Record

CVE-2021-41838: An issue was discovered in SdHostDriver in the kernel 5.0 through 5.5 in Insyde InsydeH2O.

An issue was discovered in SdHostDriver 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 a Numeric Range Comparison Without a Minimum Check.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

This vulnerability affects InsydeH2O firmware, not a normal application. If present, it could let an attacker run code in System Management Mode, a highly privileged firmware layer beneath the operating system. That can undermine endpoint trust and recovery. The source bundle does not provide CVSS, confirmed exploit activity, or a complete affected-product list.

Executive priority

Treat this as high priority for firmware risk governance, especially on critical infrastructure, appliances, and hard-to-reimage systems. The immediate business task is exposure confirmation through OEM advisories, then controlled firmware remediation where affected assets are found.

Technical view

CVE-2021-41838 is an SdHostDriver SMM callout issue in InsydeH2O kernel 5.0 through 5.5. The described root cause is numeric range comparison without a minimum check, enabling SMM access and arbitrary code execution. Exposure depends on whether OEM firmware includes the affected Insyde component.

Likely exposure

Exposure is likely limited to devices or appliances whose OEM firmware contains Insyde InsydeH2O kernel 5.0 through 5.5 with SdHostDriver. The bundle lists Siemens, NetApp, CERT/CC, and Insyde references, but does not enumerate specific affected models here.

Exploitation context

The bundle does not show CISA KEV listing or any cited confirmation of active exploitation. The impact is still serious because successful abuse targets firmware-level SMM execution, but exploitability details and prerequisites are not provided in the supplied sources.

Researcher notes

Key gaps are missing CVSS, absent product CPEs, and no exploit-prerequisite detail in the bundle. Focus research on OEM firmware lineage, SdHostDriver presence, and advisory cross-mapping. Avoid assuming Siemens or NetApp product impact without reading their linked advisories.

Mitigation direction

  • Check Insyde SA-2022023 and OEM advisories for fixed firmware guidance.
  • Prioritize vendor-approved BIOS or firmware updates for confirmed affected assets.
  • Review Siemens SSA-306654 and NetApp NTAP-20220222-0001 for environment relevance.
  • Escalate unsupported affected firmware to asset owners for replacement or compensating controls.

Validation and detection

  • Inventory systems and appliances using InsydeH2O firmware.
  • Confirm whether firmware uses InsydeH2O kernel 5.0 through 5.5.
  • Ask OEM support whether SdHostDriver is present in deployed firmware.
  • Track remediation status against vendor advisory identifiers and firmware versions.
Prepared
Confidence
medium
Sources
6

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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description · low confidence lookup

Execution behavior lookup

The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

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CVE-2021-41838 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
6Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.