Vulnerability · NVD
CVE-2026-21265
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.
Show raw CVSS vector
OS versions that fix this CVE
This CVE is resolved by the following OS security releases. Update the OS to at least the listed version.
- Windows Server 2025 Fixed in 10.0.26100.32230
- Windows Server 2022 (Server Core installation) Fixed in 10.0.20348.4648
- Windows Server 2022 Fixed in 10.0.25398.2092
- Windows Server 2019 Fixed in 10.0.17763.8276
- Windows Server 2016 Fixed in 10.0.14393.8783
- Windows 11 25H2 · 2025-H2 Fixed in 10.0.26200.7623
- Windows 11 24H2 · 2024-H2 Fixed in 10.0.26100.7623
- Windows 11 23H2 · 2023-H2 Fixed in 10.0.22631.6491
- Windows 10 22H2 · 2022-H2 Fixed in 10.0.19045.6809
- Windows 10 21H2 · 2021-H2 Fixed in 10.0.19044.6809
- Windows 10 1809 · 2018-09 Fixed in 10.0.17763.8276
- Windows 10 1607 · 2016-07 Fixed in 10.0.14393.8783