CVE-2021-38489

HDD password disclosure via plaintext UEFI variable

Published Sep 3, 2026 · Updated Sep 3, 2026

Plaintext credential storage in Insyde Software InsydeH2O allows local users with high privileges to read the HDD password. The HddPasswordPei driver stores the HDD password without encryption in a UEFI variable, leaving the credential directly readable. Exploitation requires local high-privilege access on an affected x86 system and exposes the credential protecting the disk.

CVSS severity8.2
High
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Plaintext credential storage in Insyde Software InsydeH2O allows local users with high privileges to read the HDD password. The HddPasswordPei driver stores the HDD password without encryption in a UEFI variable, leaving the credential directly readable. Exploitation requires local high-privilege access on an affected x86 system and exposes the credential protecting the disk.

The record

CVE
CVE-2021-38489
Published
Sep 3, 2026
Updated
Sep 3, 2026
Vendor
Insyde Software
Product
InsydeH2O UEFI BIOS
Classifications
CWE-256, T1555
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Sep 3, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 3, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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  1. Affected versionversion=See in the Solution

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Insyde Software · InsydeH2O UEFI BIOSversion=See in the Solution

Published CVSS scores

8.2Insyde Software CNACVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-256Unprotected Storage of Credentials
T1555Credentials from Password Stores

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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