CVE-2026-20804
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 · uneditedIncorrect privilege assignment in Windows Hello allows an unauthorized attacker to perform tampering locally.
In the news
Third-party coverage- Microsoft January 2026 Patch Tuesday fixes 3 zero-days, 114 flaws
- Microsoft CVE Summary - Bleeping Computer
Surfaced from public web coverage — external links open in a new tab.
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 confidenceThis vulnerability in Windows Hello involves incorrect privilege assignment that allows a local, unauthorized attacker to perform tampering operations. The issue stems from improper permission boundaries within the Windows Hello biometric authentication system, enabling an attacker with local access to modify system state or authentication data beyond their intended privileges.
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< 10.0.14393.8783< 10.0.17763.8276< 10.0.19044.6809< 10.0.19045.6809< 10.0.22631.6491< 10.0.26100.7623< 10.0.26200.7623< 10.0.14393.8783CVSS 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
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
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 checksWork through these to decide whether this CVE applies to you.
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Check Windows version and build numberOpen Command Prompt and run 'winver' or 'systeminfo | findstr /B /C:"OS Version"' to retrieve the full Windows build versionAffected if The displayed build version falls below any of these thresholds: 10.0.14393.8783 (Windows 10 1607/Server 2016), 10.0.17763.8276 (Windows 10 1809), 10.0.19044.6809 (Windows 10 21h2), 10.0.19045.6809 (Windows 10 22h2), 10.0.22631.6491 (Windows 11 23h2), 10.0.26100.7623 (Windows 11 24h2), or 10.0.26200
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Confirm Windows Hello biometric authentication is enabledOpen Settings, navigate to Accounts > Sign-in options, or run 'Get-Process Hello' in PowerShell to check if Windows Hello is configured on the systemAffected if Windows Hello is enabled and the Windows version is below the patched builds listed above
A system is affected if it runs a Windows version within the listed affected families and the build number is lower than the specified patch threshold, and Windows Hello biometric authentication is in use.
Generated from the published advisory. Verify against your own configuration.
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 · scoped10.0.14393.878310.0.17763.827610.0.19044.6809
Apply Microsoft security updates for Windows Hello and review authentication configuration settings to ensure proper privilege boundaries are enforced.
Windows 10 1607/Server 2016: 10.0.14393.8783 | Windows 10 1809: 10.0.17763.8276 | Windows 10 21h2: 10.0.19044.6809 | Windows 10 22h2: 10.0.19045.6809 | Windows 11 23h2: 10.0.22631.6491 | Windows 11 24h2: 10.0.26100.7623 | Windows 11 25h2: 10.0.26200.7623
- Identify the current Windows version and build number by running 'winver' or 'systeminfo' in Command Prompt
- Determine if the current build number is below the fixed version for your Windows edition
- Back up critical data before applying updates
- Apply the latest Windows security updates via Windows Update, or download updates from Microsoft Update Catalog
- Restart the system after updates are installed
- Verify the new build number meets or exceeds the fixed version threshold
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation3.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,272.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-20804 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-20804 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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