CVE-2026-45654

Administrator-level Secure Boot enforcement bypass

Published Jun 9, 2026 · Updated Jun 9, 2026

Improper access control in Windows Secure Boot allows local users with administrative privileges to bypass trusted boot enforcement. Microsoft has not disclosed the affected Secure Boot locus or the access-control operation that fails on untrusted input. Exploitation requires local high privileges and can compromise confidentiality and integrity beyond the vulnerable component, without a reported availability impact.

CVSS severity7.9
High
EPSS probability0.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Improper access control in Windows Secure Boot allows local users with administrative privileges to bypass trusted boot enforcement. Microsoft has not disclosed the affected Secure Boot locus or the access-control operation that fails on untrusted input. Exploitation requires local high privileges and can compromise confidentiality and integrity beyond the vulnerable component, without a reported availability impact.

The record

CVE
CVE-2026-45654
Published
Jun 9, 2026
Updated
Jun 9, 2026
Vendor
Microsoft
Product
Windows Server 2025 (Server Core installation)
Classifications
CWE-284
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Jun 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=10.0.26100.0 <10.0.26100.32995

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Microsoft · Windows Server 2025 (Server Core installation)version=10.0.26100.0 <10.0.26100.32995
Microsoft · Windows 11, version 25H2version=10.0.26200.0 <10.0.26200.8655
Microsoft · Windows 11, version 24H2version=10.0.26100.0 <10.0.26100.8655
Microsoft · Windows 11, version 26H1version=1.0.0 <10.0.28000.2269; version=10.0.28000.0 <10.0.28000.2269
Microsoft · Windows Server 2025version=10.0.26100.0 <10.0.26100.32995

Published CVSS scores

7.9Microsoft CorporationCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-284Improper Access Control

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo