CVE-2024-26240

Secure Boot bypass via malicious BCD file

Published Apr 9, 2024 · Updated May 3, 2025

Improper input validation in Microsoft Windows allows attackers to bypass Secure Boot by installing a malicious BCD file. Microsoft identifies Windows Boot Manager and related components but has not disclosed the exact validation operation that accepts the file. Exploitation requires physical access or administrative rights to the device, enabling unauthorized code to evade the trusted pre-OS boot policy.

CVSS severity8.0
High
EPSS probability1.06%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in Microsoft Windows allows attackers to bypass Secure Boot by installing a malicious BCD file. Microsoft identifies Windows Boot Manager and related components but has not disclosed the exact validation operation that accepts the file. Exploitation requires physical access or administrative rights to the device, enabling unauthorized code to evade the trusted pre-OS boot policy.

The record

CVE
CVE-2024-26240
Published
Apr 9, 2024
Updated
May 3, 2025
Vendor
Microsoft
Product
Windows 10 Version 1507
Classifications
CWE-20, T1542.003
Attack vector
adjacent
Privileges
Unavailable

Timeline

How it unfolded

  1. Apr 9, 2024CVE publishedPublication date reported by the CVE source.
  2. May 3, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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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 <10.0.10240.20596

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesUnavailable in this record.

What is affected?

Microsoft · Windows 10 Version 1507version=10.0.10240.0 <10.0.10240.20596
Microsoft · Windows Server 2019version=10.0.17763.0 <10.0.17763.5696
Microsoft · Windows Server 2016 (Server Core installation)version=10.0.14393.0 <10.0.14393.6897
Microsoft · Windows 11 version 21H2version=10.0.0 <10.0.22000.2899
Microsoft · Windows Server 2012 (Server Core installation)version=6.2.9200.0 <6.2.9200.24821
Microsoft · Windows Server 2012version=6.2.9200.0 <6.2.9200.24821
Microsoft · Windows 10 Version 21H2version=10.0.19043.0 <10.0.19044.4291
Microsoft · Windows Server 2022, 23H2 Edition (Server Core installation)version=10.0.25398.0 <10.0.25398.830
Microsoft · Windows Server 2016version=10.0.14393.0 <10.0.14393.6897
Microsoft · Windows 11 Version 22H3version=10.0.22631.0 <10.0.22631.3447
Microsoft · Windows Server 2008 R2 Service Pack 1version=6.1.7601.0 <6.1.7601.27067
Microsoft · Windows Server 2008 R2 Service Pack 1 (Server Core installation)version=6.1.7601.0 <6.1.7601.27067
Microsoft · Windows 10 Version 22H2version=10.0.19045.0 <10.0.19045.4291
Microsoft · Windows Server 2012 R2 (Server Core installation)version=6.3.9600.0 <6.3.9600.21924
Microsoft · Windows Server 2019 (Server Core installation)version=10.0.17763.0 <10.0.17763.5696
Microsoft · Windows 11 Version 23H2version=10.0.22631.0 <10.0.22631.3447
Microsoft · Windows 11, version 22H2version=10.0.22621.0 <10.0.22621.3447
Microsoft · Windows 10 Version 1607version=10.0.14393.0 <10.0.14393.6897
Microsoft · Windows Server 2008 Service Pack 2version=6.0.6003.0 <6.0.6003.22618
Microsoft · Windows Server 2022version=10.0.20348.0 <10.0.20348.2402
Microsoft · Windows 10 Version 1809version=10.0.0 <10.0.17763.5696; version=10.0.17763.0 <10.0.17763.5696
Microsoft · Windows Server 2012 R2version=6.3.9600.0 <6.3.9600.21924
Microsoft · Windows Server 2008 Service Pack 2 (Server Core installation)version=6.0.6003.0 <6.0.6003.22618

Published CVSS scores

8.0Microsoft CorporationCVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
7.0Microsoft Security Response CenterCVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

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

Weakness, pattern, technique

CWE-20Improper Input Validation
T1542.003Pre-OS Boot: Bootkit

Public exploit references

No public exploit references are available in this record.

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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