CVE-2024-20666 — BitLocker Security Feature Bypass Vulnerability

Executive Summary

None

Overview

6.6

CVSS MEDIUM

Important

MS Severity

Not Exploited

MS Exploit Status

Less Likely

MS Exploit Likelihood

Category Security Feature Bypass

Weakness CWE-20: Improper Input Validation

Released Jan 9 2024

Last Updated Jan 9 2024

Publicly Disclosed No

CISA KEV Not Listed

Known Exploits None Known

EPSS Score 0.03104 — 0.86601 percentile

NVD CVSS 6.6 MEDIUM — matches MSRC

CVSS Vector

CVSS:3.1/AV:P/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

ATTACK VECTOR

Physical

ATTACK COMPLEXITY

Low

PRIVILEGES REQUIRED

Low

USER INTERACTION

None

SCOPE

Unchanged

CONFIDENTIALITY

High

INTEGRITY

High

AVAILABILITY

High

EXPLOIT CODE MATURITY

Unproven

REMEDIATION LEVEL

Official Fix

REPORT CONFIDENCE

Confirmed

Temporal Score: 5.8

EPSS Score

0.03104

probability of exploitation in the next 30 days

0.86601 percentile - updated 2026-08-14

View on FIRST.org

Affected Products

26 affected products

Product	KB Article	Severity	Impact	Restart Required
Windows 10 for 32-bit Systems	`5034134 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 for x64-based Systems	`5034134 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 1607 for 32-bit Systems	`5034119 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 1607 for x64-based Systems	`5034119 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 1809 for 32-bit Systems	`5034127 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 1809 for ARM64-based Systems	`5034127 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 1809 for x64-based Systems	`5034127 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 21H2 for 32-bit Systems	`5034122 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 21H2 for ARM64-based Systems	`5034122 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 21H2 for x64-based Systems	`5034122 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 22H2 for 32-bit Systems	`5034122 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 22H2 for ARM64-based Systems	`5034122 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 22H2 for x64-based Systems	`5034122 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 11 version 21H2 for ARM64-based Systems	`5034121 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 11 version 21H2 for x64-based Systems	`5034121 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 11 Version 22H2 for ARM64-based Systems	`5034123 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 11 Version 22H2 for x64-based Systems	`5034123 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 11 Version 23H2 for ARM64-based Systems	`5034123 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 11 Version 23H2 for x64-based Systems	`5034123 (Security Update)`	Important	Security Feature Bypass	Yes
Windows Server 2016	`5034119 (Security Update)`	Important	Security Feature Bypass	Yes
Windows Server 2016 (Server Core installation)	`5034119 (Security Update)`	Important	Security Feature Bypass	Yes
Windows Server 2019	`5034127 (Security Update)`	Important	Security Feature Bypass	Yes
Windows Server 2019 (Server Core installation)	`5034127 (Security Update)`	Important	Security Feature Bypass	Yes
Windows Server 2022	`5034129 (Security Update)`	Important	Security Feature Bypass	Yes
Windows Server 2022 (Server Core installation)	`5034129 (Security Update)`	Important	Security Feature Bypass	Yes
Windows Server 2022, 23H2 Edition (Server Core installation)	`5034130 (Security Update)`	Important	Security Feature Bypass	Yes

Patches

8 patches

Article	Type	Restart
`5034134`	Security Update	Yes
`5034119`	Security Update	Yes
`5034127`	Security Update	Yes
`5034122`	Security Update	Yes
`5034121`	Security Update	Yes
`5034123`	Security Update	Yes
`5034129`	Security Update	Yes
`5034130`	Security Update	Yes

Exploits & PoC

3 public PoCs

Unverified third-party code

Public proof-of-concept repositories aggregated from PoC-in-GitHub. They are not reviewed and may be incomplete, non-functional, or malicious — inspect the code before running anything.

Repository	Stars	Published	Description
nnotwen/Script-For-CVE-2024-20666	4	2024-02-15	PowerShell script that can help you automate updating the Windows Recovery Environment (WinRE) on deployed devices to address the security vulnerabilities in CVE-2024-20666.
invaderslabs/CVE-2024-20666	1	2024-07-01	CVE-2024-20666 vulnerability Solution patch failures in the Windows Recovery Environment (WinRE).
tazxtazxedu/WinRE-Fix	1	2025-11-28	PowerShell script to fix WinRE/Recovery partition issues - KB5034441, KB5028997, CVE-2024-20666 Windows Update failures

Detection Rules

No public Sigma or Nuclei detection rule has been mapped to this CVE yet. Coverage is concentrated on exploited / high-profile vulnerabilities; check SigmaHQ for updates.

Acknowledgments

Zammis Clark

References

MSRC Advisory MITRE NVD