CVE-2026-0390: UEFI Secure Boot Security Feature Bypass Vulnerability

Severity: medium (CVSS 6.7 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-04-14 · updated 2026-10-25
Weakness: CWE-807

Description

Reliance on untrusted inputs in a security decision in Windows Boot Loader allows an authorized attacker to bypass a security feature locally.

Affected products

Microsoft Windows 10 1607: before 10.0.14393.9060 — fixed in 10.0.14393.9060
Microsoft Windows 10: before 10.0.17763.8644 — fixed in 10.0.17763.8644
Microsoft Windows 10: before 10.0.19044.7184 — fixed in 10.0.19044.7184
Microsoft Windows 10: before 10.0.19045.7184 — fixed in 10.0.19045.7184
Microsoft Windows Server 2016: before 10.0.14393.9060 — fixed in 10.0.14393.9060
Microsoft Windows Server 2019: before 10.0.17763.8644 — fixed in 10.0.17763.8644
Microsoft Windows Server 2022: before 10.0.20348.5020 — fixed in 10.0.20348.5020
Microsoft Windows 10 1607: from 10.0.14393.0 before 10.0.14393.9060 — fixed in 10.0.14393.9060
Microsoft Windows 10: from 10.0.17763.0 before 10.0.17763.8644 — fixed in 10.0.17763.8644
Microsoft Windows 10: from 10.0.19044.0 before 10.0.19044.7184 — fixed in 10.0.19044.7184
Microsoft Windows 10: from 10.0.19045.0 before 10.0.19045.7184 — fixed in 10.0.19045.7184
Microsoft Windows Server 2016: from 10.0.14393.0 before 10.0.14393.9060 — fixed in 10.0.14393.9060
Microsoft Windows Server 2019: from 10.0.17763.0 before 10.0.17763.8644 — fixed in 10.0.17763.8644
Microsoft Windows Server 2022: from 10.0.20348.0 before 10.0.20348.5020 — fixed in 10.0.20348.5020

How to fix

Upgrade to a fixed version: Microsoft Windows 10 1607 10.0.14393.9060; Microsoft Windows 10 10.0.17763.8644; Microsoft Windows 10 10.0.19044.7184; Microsoft Windows 10 10.0.19045.7184; Microsoft Windows Server 2016 10.0.14393.9060; Microsoft Windows Server 2019 10.0.17763.8644; Microsoft Windows Server 2022 10.0.20348.5020; Microsoft Windows 10 1607 10.0.14393.9060; Microsoft Windows 10 10.0.17763.8644; Microsoft Windows 10 10.0.19044.7184; Microsoft Windows 10 10.0.19045.7184; Microsoft Windows Server 2016 10.0.14393.9060. Check the vendor advisory for mitigations.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-0390

Get alerted when CVE-2026-0390 or the next vulnerability affects your stack