dbcve.org
Windows 10 1607Operating system · Microsoft

CVE-2026-34335

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
Use after free 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 · moderate confidence

Use after free vulnerability in Windows Ancillary Function Driver for WinSock enables a locally authorized attacker to elevate privileges to higher integrity levels by exploiting memory management in the Winsock kernel component.

MitigationDeploy Microsoft security updates addressing this vulnerability when released; given the local privilege escalation risk, prioritize patching workstations and servers in high-privilege environments.

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"' to view the installed Windows build number
    Affected if The build number is lower than any of these: 14393.9234 (Win10 1607), 17763.8880 (Win10 1809), 19044.7417 (Win10 21h2), 19045.7417 (Win10 22h2), 22631.7219 (Win11 23h2), 26100.8655 (Win11 24h2), 26200.8655 (Win11 25h2), 28000.2269 (Win11 26h1)
  2. Verify AFD driver presence
    Open File Explorer, navigate to C:\Windows\System32\drivers\afd.sys, right-click and view Properties > Details to see the File Version
    Affected if The driver file version is present and corresponds to an unpatched Windows build from the affected version list
  3. Confirm kernel driver is loaded
    Run 'sc query afd' in Command Prompt to check if the AFD driver service is running
    Affected if The service state is RUNNING (this driver is required for Winsock and typically loads on startup)

You are affected if your Windows build version is lower than the fixed versions listed for your Windows release, and the AFD driver is loaded on your 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 10.0.14393.9234 / 10.0.17763.8880 / 10.0.19044.7417 or later
Fixed in 10.0.14393.923410.0.17763.888010.0.19044.7417
Interim mitigation

Deploy Microsoft security updates addressing this vulnerability when released; given the local privilege escalation risk, prioritize patching workstations and servers in high-privilege environments.

Recommended fix High confidence

Windows 10 1607: build 10.0.14393.9234 or later | Windows 10 1809: build 10.0.17763.8880 or later | Windows 10 21h2: build 10.0.19044.7417 or later | Windows 10 22h2: build 10.0.19045.7417 or later | Windows 11 23h2: build 10.0.22631.7219 or later | Windows 11 24h2: build 10.0.26100.8655 or later |

  1. 1. Identify the current Windows version and build by running 'winver' or 'systeminfo' in Command Prompt
  2. 2. Determine which Windows 10 or 11 version and build is currently installed
  3. 3. Navigate to Windows Update: Settings > Update & Security > Windows Update
  4. 4. Check for updates and install all available security updates
  5. 5. Alternatively, download the specific security update from Microsoft Update Catalog for the detected Windows version
  6. 6. After installation, restart the system to apply the update
  7. 7. Verify the build number matches or exceeds the fixed version for your Windows release
Caveat Standard Windows security update; no expected breaking changes for typical workloads

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

Fix this in Windows 10 1607 Scoped from the published advisory
  • Consultation3.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
17.0 hours of engineering $3,000
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,800.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

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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-2026-34335 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