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Windows 10 1607Operating system · Microsoft

CVE-2026-0390

MEDIUM · 6.7 CVSS v3.1 Published 2026-04-14
Fix available
A fix is available. Upgrade to 10.0.14393.9060 / 10.0.17763.8644 or later.
See remediation →
69/100
Remediation priority · Elevated
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

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

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

This is a local privilege escalation/-security bypass vulnerability in the Windows Boot Loader. The flaw stems from the boot loader trusting untrusted inputs (possibly from external media, firmware, or configuration) when making security decisions, allowing an authorized local attacker to bypass a security feature (likely Secure Boot or similar boot integrity mechanisms).

MitigationApply Microsoft security patches for affected Windows versions once released. Until then, restrict physical access to systems, disable boot from unauthorized media in firmware settings, and enable tamper detection on boot integrity features.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Windows 10 1607Operating system
Affected:< 10.0.14393.9060
Windows 10 1809Operating system
Affected:< 10.0.17763.8644
Windows 10 21h2Operating system
Affected:< 10.0.19044.7184
Windows 10 22h2Operating system
Affected:< 10.0.19045.7184
Windows Server 2016Operating system
Affected:< 10.0.14393.9060
Windows Server 2019Operating system
Affected:< 10.0.17763.8644
Windows Server 2022Operating system
Affected:< 10.0.20348.5020

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
High
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check installed Windows version
    Run 'winver' from the command line or view 'systeminfo' output to find the OS build number displayed as 'Version'
    Affected if The build number is lower than 10.0.14393.9060 (Windows 10 1607/Server 2016), 10.0.17763.8644 (Windows 10 1809/Server 2019), 10.0.19044.7184 (Windows 10 21h2), 10.0.19045.7184 (Windows 10 22h2), or 10.0.20348.5020 (Windows Server 2022)
  2. Confirm exact build number via registry
    Run 'reg query "HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion" /v CurrentBuild' and check the CurrentBuild value
    Affected if The retrieved build number is lower than the affected thresholds listed above for your specific Windows release
  3. Identify Windows release name
    Run 'reg query "HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion" /v ReleaseId' to determine the release version (e.g., 1607, 1809, 21h2, 22h2)
    Affected if The release ID combined with the build number falls into an affected version range
  4. Check UEFI/BIOS boot order settings
    Access system firmware settings (via BIOS setup or UEFI configuration) and examine boot order priority, specifically whether external media (USB, CD/DVD, network boot) is listed before the internal hard drive
    Affected if Boot from external/unauthorized media is enabled and prioritized above the primary OS drive, allowing an attacker to inject untrusted inputs at boot time
  5. Verify Secure Boot status
    Run 'Confirm-SecureBootUEFI' from PowerShell (requires Administrator) to check if Secure Boot is enabled
    Affected if Secure Boot is disabled, as the vulnerability exploits the boot loader's trust of untrusted inputs when boot integrity mechanisms are not active

Your system is affected if it runs any Windows 10 version or Windows Server version/2022 with a build number lower than the specified threshold for that release AND an attacker could boot from unauthorized media or bypass boot integrity protections.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 10.0.14393.9060 / 10.0.17763.8644 / 10.0.19044.7184 or later
Fixed in 10.0.14393.906010.0.17763.864410.0.19044.7184
Interim mitigation

Apply Microsoft security patches for affected Windows versions once released. Until then, restrict physical access to systems, disable boot from unauthorized media in firmware settings, and enable tamper detection on boot integrity features.

Recommended fix Moderate confidence

Upgrade to Windows 10 build 10.0.14393.9060 or later for version 1607/Server 2016; build 10.0.17763.8644 or later for version 1809/Server 2019; build 10.0.19044.7184 or later for 21h2; build 10.0.19045.7184 or later for 22h2; or build 10.0.20348.5020 or later for Windows Server 2022

  1. Check current Windows build version by running 'winver' or 'systeminfo' in command prompt
  2. Identify which Windows version and build you are running from the affected list (1607/10.0.14393, 1809/10.0.17763, 21h2/10.0.19044, 22h2/10.0.19045, Server 2016/2019/2022)
  3. Apply the appropriate Windows Security Update that includes the fix for CVE-2026-0390. This is typically a cumulative update or a specific security update from Microsoft Update Catalog
  4. Restart the system after applying the update
  5. Verify the installation was successful by checking the build version matches or exceeds the fixed version: 10.0.14393.9060 (1607/Server 2016), 10.0.17763.8644 (1809/Server 2019), 10.0.19044.7184 (21h2), 10.0.19045.7184 (22h2), or 10.0.20348.5020 (Server 2022)
Caveat Standard Windows update risks apply - ensure backups are made and compatibility is verified for critical systems before applying

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Windows 10 1607 Scoped from the published advisory
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing4.0 h
  • Review / QA2.0 h
9.0 hours of engineering $1,540
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Scan for this in your stack

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dbcve dependency scanner

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-0390 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data