Administrator-level UEFI Secure Boot bypass
Published Apr 14, 2026 · Updated Apr 14, 2026
Security feature bypass in Windows Boot Loader on affected Windows releases allows local users with administrative rights to defeat UEFI Secure Boot. Microsoft identifies reliance on untrusted inputs in a security decision but has not disclosed the input, decision point, or validation operation that accepts it. Exploitation requires local high privileges and can undermine the boot trust boundary, with confidentiality, integrity, and availability impacts.
Summary
What happened
Security feature bypass in Windows Boot Loader on affected Windows releases allows local users with administrative rights to defeat UEFI Secure Boot. Microsoft identifies reliance on untrusted inputs in a security decision but has not disclosed the input, decision point, or validation operation that accepts it. Exploitation requires local high privileges and can undermine the boot trust boundary, with confidentiality, integrity, and availability impacts.
The record
- CVE
- CVE-2026-0390
- Published
- Apr 14, 2026
- Updated
- Apr 14, 2026
- Vendor
- Microsoft
- Product
- Windows Server 2019
- Classifications
- CWE-807, T1542.003
- Attack vector
- local
- Privileges
- admin
Timeline
How it unfolded
- Apr 14, 2026CVE publishedPublication date reported by the CVE source.
- Apr 14, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=10.0.17763.0 <10.0.17763.8644
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Weakness, pattern, technique
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
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Your stack
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