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

Executive Summary

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

Overview

6.7

CVSS MEDIUM

Important

MS Severity

Not Exploited

MS Exploit Status

More Likely

MS Exploit Likelihood

Category Security Feature Bypass

Released Apr 14 2026

Last Updated Apr 14 2026

Publicly Disclosed No

CISA KEV Not Listed

Known Exploits None Known

EPSS Score 0.00318 — 0.23309 percentile

NVD CVSS 6.7 MEDIUM — matches MSRC

CVSS Vector

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

ATTACK VECTOR

Local

ATTACK COMPLEXITY

Low

PRIVILEGES REQUIRED

High

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

0.00318

probability of exploitation in the next 30 days

0.23309 percentile - updated 2026-06-21

View on FIRST.org

Affected Products

16 affected products

Product	KB Article	Severity	Impact	Restart Required
Windows 10 Version 1607 for 32-bit Systems	`5082198 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 1607 for x64-based Systems	`5082198 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 1809 for 32-bit Systems	`5082123 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 1809 for x64-based Systems	`5082123 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 21H2 for 32-bit Systems	`5082200 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 21H2 for ARM64-based Systems	`5082200 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 21H2 for x64-based Systems	`5082200 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 22H2 for 32-bit Systems	`5082200 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 22H2 for ARM64-based Systems	`5082200 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 22H2 for x64-based Systems	`5082200 (Security Update)`	Important	Security Feature Bypass	Yes
Windows Server 2016	`5082198 (Security Update)`	Important	Security Feature Bypass	Yes
Windows Server 2016 (Server Core installation)	`5082198 (Security Update)`	Important	Security Feature Bypass	Yes
Windows Server 2019	`5082123 (Security Update)`	Important	Security Feature Bypass	Yes
Windows Server 2019 (Server Core installation)	`5082123 (Security Update)`	Important	Security Feature Bypass	Yes
Windows Server 2022	`5082142 (Security Update)`	Important	Security Feature Bypass	Yes
Windows Server 2022 (Server Core installation)	`5082142 (Security Update)`	Important	Security Feature Bypass	Yes

Patches

4 patches

Article	Type	Restart
`5082198`	Security Update	Yes
`5082123`	Security Update	Yes
`5082200`	Security Update	Yes
`5082142`	Security Update	Yes

Known Exploits

No known exploits have been linked for this CVE yet. When available, exploit references will be sourced from public repositories and may be unverified, incomplete, or non-functional. Always review code carefully before use in any environment.

Acknowledgments

Alon Leviev

References

MSRC Advisory MITRE NVD