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Unrated severityNVD Advisory· Published Jan 13, 2026· Updated Apr 1, 2026

Secure Boot Certificate Expiration Security Feature Bypass Vulnerability

CVE-2026-21265

Description

Windows Secure Boot stores Microsoft certificates in the UEFI KEK and DB. These original certificates are approaching expiration, and devices containing affected certificate versions must update them to maintain Secure Boot functionality and avoid compromising security by losing security fixes related to Windows boot manager or Secure Boot. The operating system’s certificate update protection mechanism relies on firmware components that might contain defects, which can cause certificate trust updates to fail or behave unpredictably. This leads to potential disruption of the Secure Boot trust chain and requires careful validation and deployment to restore intended security guarantees.

Certificate Authority (CA) Location Purpose Expiration Date

Microsoft Corporation KEK CA 2011 KEK Signs updates to the DB and DBX 06/24/2026

Microsoft Corporation UEFI CA 2011 DB Signs 3rd party boot loaders, Option ROMs, etc. 06/27/2026

Microsoft Windows Production PCA 2011 DB Signs the Windows Boot Manager 10/19/2026

For more information see this CVE and Windows Secure Boot certificate expiration and CA updates.

Affected products

21
  • Microsoft/Windows Secure Bootllm-create
  • Microsoft/Windows 10 Version 1607v5
    Range: 10.0.14393.0
  • Microsoft/Windows 10 Version 1809v5
    Range: 10.0.17763.0
  • Microsoft/Windows 10 Version 21H2v5
    Range: 10.0.19044.0
  • Microsoft/Windows 10 Version 22H2v5
    Range: 10.0.19045.0
  • Microsoft/Windows 11 version 22H3v5
    Range: 10.0.22631.0
  • Microsoft/Windows 11 Version 23H2v5
    Range: 10.0.22631.0
  • Microsoft/Windows 11 Version 24H2v5
    Range: 10.0.26100.0
  • Microsoft/Windows 11 Version 25H2v5
    Range: 10.0.26200.0
  • Microsoft/Windows Server 2012v5
    Range: 6.2.9200.0
  • Microsoft/Windows Server 2012 R2v5
    Range: 6.3.9600.0
  • Microsoft/Windows Server 2012 R2 (Server Core installation)v5
    Range: 6.3.9600.0
  • Microsoft/Windows Server 2012 (Server Core installation)v5
    Range: 6.2.9200.0
  • Microsoft/Windows Server 2016v5
    Range: 10.0.14393.0
  • Microsoft/Windows Server 2016 (Server Core installation)v5
    Range: 10.0.14393.0
  • Microsoft/Windows Server 2019v5
    Range: 10.0.17763.0
  • Microsoft/Windows Server 2019 (Server Core installation)v5
    Range: 10.0.17763.0
  • Microsoft/Windows Server 2022v5
    Range: 10.0.20348.0
  • Microsoft/Windows Server 2022, 23H2 Edition (Server Core installation)v5
    Range: 10.0.25398.0
  • Microsoft/Windows Server 2025v5
    Range: 10.0.26100.0
  • Microsoft/Windows Server 2025 (Server Core installation)v5
    Range: 10.0.26100.0

Patches

0

No patches discovered yet.

Vulnerability mechanics

AI mechanics synthesis has not run for this CVE yet.

References

1

News mentions

0

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