CVE-2023-21563Public exploit

Encrypted-drive access via uncleared preboot key

Published Jan 10, 2023 · Updated Jan 1, 2025

Security feature bypass in Microsoft Windows allows physically proximate attackers to access BitLocker-encrypted system drives. Windows Boot Manager unseals the volume master key before loading the operating system, then leaves that key in memory after a failed PXE boot and soft reboot. Exploitation requires TPM-only BitLocker, PXE boot capability, and a PCR profile excluding PCR 4; recovered keys permit reading or altering the encrypted volume.

CVSS severity6.8
Medium
EPSS probability1.55%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Security feature bypass in Microsoft Windows allows physically proximate attackers to access BitLocker-encrypted system drives. Windows Boot Manager unseals the volume master key before loading the operating system, then leaves that key in memory after a failed PXE boot and soft reboot. Exploitation requires TPM-only BitLocker, PXE boot capability, and a PCR profile excluding PCR 4; recovered keys permit reading or altering the encrypted volume.

The record

CVE
CVE-2023-21563
Published
Jan 10, 2023
Updated
Jan 1, 2025
Vendor
Microsoft
Product
Windows 10 Version 1507
Classifications
T1006
Attack vector
physical
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 10, 2023CVE publishedPublication date reported by the CVE source.
  2. Jan 1, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=10.0.10240.0 <10.0.10240.19685

What conditions does exploitation require?

Attack vectorphysical
Required privilegesunauthenticated

What is affected?

Microsoft · Windows 10 Version 1507version=10.0.10240.0 <10.0.10240.19685
Microsoft · Windows Server 2019version=10.0.17763.0 <10.0.17763.3887
Microsoft · Windows 7version=6.1.0 <6.1.7601.26321
Microsoft · Windows 8.1version=6.3.0 <6.3.9600.20778
Microsoft · Windows Server 2016 (Server Core installation)version=10.0.14393.0 <10.0.14393.5648
Microsoft · Windows 11 version 21H2version=10.0.0 <10.0.22000.1455
Microsoft · Windows Server 2012 (Server Core installation)version=6.2.9200.0 <6.2.9200.24075
Microsoft · Windows Server 2012version=6.2.9200.0 <6.2.9200.24075
Microsoft · Windows 10 Version 21H2version=10.0.19043.0 <10.0.19044.2486
Microsoft · Windows Server 2016version=10.0.14393.0 <10.0.14393.5648
Microsoft · Windows Server 2008 R2 Service Pack 1version=6.1.7601.0 <6.1.7601.26321
Microsoft · Windows 10 Version 20H2version=10.0.0 <10.0.19042.2486
Microsoft · Windows Server 2008 R2 Service Pack 1 (Server Core installation)version=6.1.7601.0 <6.1.7601.26321
Microsoft · Windows 10 Version 22H2version=10.0.19045.0 <10.0.19045.2486
Microsoft · Windows Server 2012 R2 (Server Core installation)version=6.3.9600.0 <6.3.9600.20778
Microsoft · Windows Server 2019 (Server Core installation)version=10.0.17763.0 <10.0.17763.3887
Microsoft · Windows 7 Service Pack 1version=6.1.0 <6.1.7601.26321
Microsoft · Windows 11, version 22H2version=10.0.22621.0 <10.0.22621.1105
Microsoft · Windows 10 Version 1607version=10.0.14393.0 <10.0.14393.5648
Microsoft · Windows Server 2008 Service Pack 2version=6.0.6003.0 <6.0.6003.21872
Microsoft · Windows Server 2022version=10.0.20348.0 <10.0.20348.1487
Microsoft · Windows 10 Version 1809version=10.0.0 <10.0.17763.3887; version=10.0.17763.0 <10.0.17763.3887
Microsoft · Windows Server 2012 R2version=6.3.9600.0 <6.3.9600.20778
Microsoft · Windows Server 2008 Service Pack 2 (Server Core installation)version=6.0.6003.0 <6.0.6003.21872

Published CVSS scores

6.8NIST NVDCVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
6.8Microsoft CorporationCVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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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)
Vectorphysical
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

T1006Direct Volume Access

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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