dbcve.org
Windows 10 1607Operating system · Microsoft

CVE-2026-45603

HIGH · 7.0 CVSS v3.1 Published 2026-06-09
Fix available
A fix is available. Upgrade to 10.0.14393.9234 / 10.0.17763.8880 or later.
See remediation →
72/100
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
Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges 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 · high confidence

A race condition vulnerability exists in the Windows Ancillary Function Driver (AFD.sys) for WinSock. The improper synchronization in the shared kernel resource allows a local authorized attacker to manipulate timing to elevate privileges to SYSTEM level.

MitigationApply the relevant Microsoft security update for Windows AFD driver when available; prioritize patching domain controllers and high-value workstations first due to the local privilege escalation risk.

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:< 10.0.14393.9234
Windows 10 1809Operating system
Affected:< 10.0.17763.8880
Windows 10 21h2Operating system
Affected:< 10.0.19044.7417
Windows 10 22h2Operating system
Affected:< 10.0.19045.7417
Windows 11 23h2Operating system
Affected:< 10.0.22631.7219
Windows 11 24h2Operating system
Affected:< 10.0.26100.8655
Windows 11 25h2Operating system
Affected:< 10.0.26200.8655
Windows 11 26h1Operating system
Affected:< 10.0.28000.2269

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 see the installed Windows build number
    Affected if The build number is lower than the fixed version for your Windows release (e.g., below 10.0.14393.9234 for Windows 10 1607, below 10.0.17763.8880 for Windows 10 1809, etc.)
  2. Identify Windows release version
    Run 'winver' to determine if you are on Windows 10 1607, 1809, 21h2, 22h2, or Windows 11 23h2, 24h2, 25h2, 26h1
    Affected if Your Windows release matches one of the affected versions and its build is below the corresponding threshold
  3. Check AFD driver file version
    Locate afd.sys in C:\Windows\System32\drivers\, right-click properties, and view the File Version details
    Affected if The driver version corresponds to a Windows build that falls within the vulnerable range for your OS release

You are affected if your Windows build number is below the threshold for your specific Windows version and the AFD driver is from an unpatched Windows installation.

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 10.0.14393.9234 / 10.0.17763.8880 / 10.0.19044.7417 or later
Fixed in 10.0.14393.923410.0.17763.888010.0.19044.7417
Interim mitigation

Apply the relevant Microsoft security update for Windows AFD driver when available; prioritize patching domain controllers and high-value workstations first due to the local privilege escalation risk.

Recommended fix High confidence

Install Microsoft security update for CVE-2026-45603 from Windows Update or Microsoft Update Catalog

  1. Identify the current Windows build version by running 'winver' or 'systeminfo' in Command Prompt
  2. Determine which Windows version and build you are running (Windows 10 1607, 1809, 21h2, 22h2, or Windows 11 23h2, 24h2, 25h2, 26h1)
  3. Open Settings > Windows Update > Check for updates, or use WSUS/Intune/SCCM to deploy updates
  4. Install the appropriate Microsoft security update for CVE-2026-45603 from msrc.microsoft.com
  5. Reboot the system after updates are installed
  6. Verify the build number has been updated to or above: 10.0.14393.9234 (Win10 1607), 10.0.17763.8880 (Win10 1809), 10.0.19044.7417 (Win10 21h2), 10.0.19045.7417 (Win10 22h2), 10.0.22631.7219 (Win11 23h2), 10.0.26100.8655 (Win11 24h2), 10.0.26200.8655 (Win11 25h2), or 10.0.28000.2269 (Win11 26h1)
Caveat Standard Windows update - no expected breaking changes; patch is specifically for this race condition vulnerability in the Windows Ancillary Function Driver for WinSock

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

Fix this in Windows 10 1607 Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
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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-2026-45603 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