dbcve.org
Windows 10 1607Operating system · Microsoft

CVE-2026-57093

HIGH · 7.8 CVSS v3.1 Published 2026-07-14
Fix available
A fix is available. Upgrade to 10.0.14393.9339 / 10.0.17763.9020 or later.
See remediation →
80/100
Remediation priority · High
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 Ancillary Function Driver for WinSock 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 exists in the Windows Ancillary Function Driver for WinSock (Afd.sys), a kernel-mode driver that handles Winsock API calls. The flaw allows a locally authorized attacker to exploit a freed memory object to elevate privileges to SYSTEM level by achieving arbitrary code execution in kernel context.

MitigationApply Microsoft security updates for Afd.sys through Windows Update or enterprise patch management systems. Prioritize endpoints based on exposure to local attackers.

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:< 10.0.14393.9339
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 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
Windows Server 2012Operating system
Affected:all versions= r2

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

CVSS:3.1/AV:L/AC:L/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 OS build version
    Run 'winver' or 'systeminfo | findstr /B /C:"OS Version"' to display the installed Windows build number
    Affected if The build number falls below any of these thresholds: 14393.9339 (1607), 17763.9020 (1809), 19044.7548 (21h2), 19045.7548 (22h2), 26100.8875 (24h2), 26200.8875 (25h2), 28000.2269 (26h1); or if running Windows Server 2012 / 2012 R2 (all versions)
  2. Check Afd.sys driver file version
    Run 'powershell "(Get-Item C:\Windows\System32\drivers\Afd.sys).VersionInfo.FileVersion"' to retrieve the driver file version
    Affected if The Afd.sys version is lower than the corresponding version for your Windows build (compare against the affected version ranges for your OS) or if running Windows Server 2012/2012 R2 where all versions are affected
  3. Verify the driver is loaded
    Run 'sc query afd' or 'powershell "Get-Service -Name afd"' to check if the Afd service is running
    Affected if The service is running (status = RUNNING); the vulnerability only applies when the driver is active to handle Winsock operations
  4. Confirm local attacker perspective
    Review event logs or check for unauthorized local accounts that could exploit this privilege escalation vulnerability
    Affected if There are untrusted local users or compromised local accounts with authenticated access to the system

You are affected if your Windows build version or Afd.sys driver version is below the affected thresholds AND the Afd.sys driver is currently loaded and handling network operations.

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 10.0.14393.9339 / 10.0.17763.9020 / 10.0.19044.7548 or later
Fixed in 10.0.14393.933910.0.17763.902010.0.19044.7548
Interim mitigation

Apply Microsoft security updates for Afd.sys through Windows Update or enterprise patch management systems. Prioritize endpoints based on exposure to local attackers.

Recommended fix High confidence

For each affected Windows version, apply the latest cumulative security update that includes the fix for this vulnerability (KB references can be found at msrc.microsoft.com for the corresponding CVE)

  1. Open Windows Update on the affected system (Start > Settings > Update & Security > Windows Update)
  2. Click 'Check for updates' and install all available security updates
  3. Alternatively, manually download and install the specific KB patch from the Microsoft Update Catalog corresponding to your Windows version and build
  4. Restart the system after applying the update
  5. Verify the installed version matches or exceeds the fixed build number for your Windows version using 'winver' or 'systeminfo'
Caveat Standard Windows security update - minimal risk of breaking changes; always test in non-production environments first

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
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA1.0 h
9.0 hours of engineering $1,600
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,560.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2026-57093 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2026-57093 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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