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Windows 10 1809Operating system · Microsoft

CVE-2026-56173

HIGH · 7.0 CVSS v3.1 Published 2026-07-14
Fix available
A fix is available. Upgrade to 10.0.17763.9020 / 10.0.19044.7548 or later.
See remediation →
72/100
Remediation priority · Elevated
Zero-click 5 weeks old

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
Use after free in Windows WebView allows an authorized attacker to elevate privileges locally.

In the news

Third-party coverage
Trending covered by 1 outlet this week · latest 1mo ago

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 confidence

A use-after-free vulnerability in Windows WebView allows an authorized local attacker to elevate privileges by exploiting memory corruption in the WebView component.

MitigationApply Microsoft security updates for Windows when available; ensure systems are patched through Windows Update. Monitor for CVE-2026-56173 patches and apply promptly.

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 1809Operating system
Affected:< 10.0.17763.9020
Windows 10 21h2Operating system
Affected:< 10.0.19044.7548
Windows 10 22h2Operating system
Affected:< 10.0.19045.7548
Windows 11 23h2Operating system
Affected:< 10.0.22631.7376
Windows 11 24h2Operating system
Affected:< 10.0.26100.8875
Windows 11 25h2Operating system
Affected:< 10.0.26200.8875
Windows 11 26h1Operating system
Affected:< 10.0.28000.2269< 10.0.28000.2525
Windows Server 2019Operating system
Affected:< 10.0.17763.9020

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
High
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:H/PR:L/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 Windows build version
    Run 'winver' or 'systeminfo | findstr /B /C:"OS Version"' to display the full build number. Compare the build number against the affected thresholds: 17763.9020 (Win 10 1809/Server 2019), 19044.7548 (Win 10 21h2), 19045.7548 (Win 10 22h2), 22631.7376 (Win 11 23h2), 26100.8875 (Win 11 24h2), 26200.8875 (Win 11 25h2), 28000.2269 or 28000.2525 (Win 11 26h1).
    Affected if The installed build number is lower than the corresponding threshold for your Windows version.
  2. Verify WebView2 Runtime is installed
    Open Settings > Apps > Installed Apps and search for 'WebView2' or 'Microsoft Edge WebView2 Runtime', or run 'Get-ItemProperty HKLM:\SOFTWARE\WOW6432Node\Microsoft\EdgeUpdate\Clients\{F3017226-FE2A-4295-8BDF-00C3A9A7E4C5}' -ErrorAction SilentlyContinue in PowerShell.
    Affected if WebView2 Runtime is present on the system; the vulnerability exists in this component.
  3. Confirm the specific security update is absent
    Run 'Get-HotFix | Where-Object {$_.Description -match "Security"} | Sort-Object InstalledOn -Descending | Select-Object -First 10' or check Windows Update history for a security update addressing CVE-2026-56173.
    Affected if No security update specifically addressing this CVE is installed.

You are affected if your Windows build falls below the version threshold for your specific Windows release AND WebView2 Runtime is installed on the system.

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 10.0.17763.9020 / 10.0.19044.7548 / 10.0.19045.7548 or later
Fixed in 10.0.17763.902010.0.19044.754810.0.19045.7548
Interim mitigation

Apply Microsoft security updates for Windows when available; ensure systems are patched through Windows Update. Monitor for CVE-2026-56173 patches and apply promptly.

Recommended fix High confidence

Windows 10 1809: 10.0.17763.9020 | Windows 10 21h2: 10.0.19044.7548 | Windows 10 22h2: 10.0.19045.7548 | Windows 11 23h2: 10.0.22631.7376 | Windows 11 24h2: 10.0.26100.8875 | Windows 11 25h2: 10.0.26200.8875 | Windows 11 26h1: 10.0.28000.2525 | Windows Server 2019: 10.0.17763.9020

  1. Check current Windows version by running `winver` or `systeminfo` in Command Prompt
  2. Identify the affected Windows edition and version from the list: Windows 10 1809, 21h2, 22h2; Windows 11 23h2, 24h2, 25h2, 26h1; or Windows Server 2019
  3. Open Windows Settings > Update & Security > Windows Update
  4. Click 'Check for updates' to download and install the latest cumulative update
  5. Verify the installed version matches or exceeds the fixed build: 10.0.17763.9020 (Windows 10 1809/Server 2019), 10.0.19044.7548 (Windows 10 21h2), 10.0.19045.7548 (Windows 10 22h2), 10.0.22631.7376 (Windows 11 23h2), 10.0.26100.8875 (Windows 11 24h2), 10.0.26200.8875 (Windows 11 25h2), or 10.0.28000.2525 (Windows 11 26h1)
  6. Alternatively, manually download and install the specific cumulative update from the Microsoft Update Catalog matching your Windows version
Caveat Standard Windows update with no expected breaking changes; as a local privilege escalation fix, this update should be applied without delay

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

Fix this in Windows 10 1809 Scoped from the published advisory
  • Consultation4.0 h
  • Implementation16.0 h
  • Testing8.0 h
  • Review / QA4.0 h
32.0 hours of engineering $5,600
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Scan for this in your stack

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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-2026-56173 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