dbcve.org
Windows 10 1607Operating system · Microsoft

CVE-2026-50312

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

This is a Use-After-Free (UAF) vulnerability in the Windows Ancillary Function Driver (afd.sys), which handles Winsock communications in kernel mode. An authorized attacker can exploit the memory management error to achieve local privilege escalation from a standard user to elevated SYSTEM privileges.

MitigationApply the Microsoft security update for this vulnerability via Windows Update or manual patch deployment. Prioritize workstations and servers with exposed attack surfaces.

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< 10.0.28000.2525
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 version and build number
    Open Command Prompt or PowerShell and run: `winver` or `systeminfo | findstr /B /C:"OS Name" /C:"OS Version"` to display the installed Windows edition, version, and build number.
    Affected if The displayed build number falls below any of these thresholds: 14393.9339 (Windows 10 1607), 17763.9020 (Windows 10 1809), 19044.7548 (Windows 10 21h2/22h2), 26100.8875 (Windows 11 24h2), 26200.8875 (Windows 11 25h2), 28000.2269 or 28000.2525 (Windows 11 26h1).
  2. Verify afd.sys driver version
    In PowerShell, run: `Get-ItemProperty -Path C:\Windows\System32\drivers\afd.sys | Select-Object Version, FileVersion, LastWriteTime` to retrieve the file version and timestamp of the affected driver.
    Affected if The driver file version is older than the versions bundled with the fixed Windows builds listed above.
  3. Confirm the vulnerability applies to your environment
    Check that the Windows Ancillary Function Driver (afd.sys) is enabled and in use. This driver is part of standard Winsock operations and is loaded by default on affected Windows systems. No additional configuration check is needed as the driver loads automatically for network socket operations.
    Affected if The system is running an affected Windows version and the afd.sys driver is present (which is the default state for Windows installations with networking enabled).

Your system is potentially affected if it runs any Windows version within the affected ranges listed above and has not applied the corresponding Microsoft security update.

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 the Microsoft security update for this vulnerability via Windows Update or manual patch deployment. Prioritize workstations and servers with exposed attack surfaces.

Recommended fix High confidence
  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 from the affected list
  3. Open Windows Update by navigating to Settings > Update & Security > Windows Update
  4. Click 'Check for updates' and install all available security updates
  5. Alternatively, manually download and install the specific cumulative security update for your Windows version from the Microsoft Update Catalog (catalog.update.microsoft.com)
  6. After installation, restart the system to apply the kernel driver update
  7. Verify the vulnerability is remediated by confirming the build number matches or exceeds the minimum fixed version for your Windows release

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
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,600.

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-2026-50312 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