CVE-2026-34351
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 · uneditedConcurrent execution using shared resource with improper synchronization ('race condition') in Windows TCP/IP 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 confidenceA race condition vulnerability exists in the Windows TCP/IP stack where concurrent execution of operations on shared resources lacks proper synchronization, allowing a locally authenticated attacker to escalate privileges to higher authority levels.
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< 10.0.14393.9140< 10.0.17763.8755< 10.0.19044.7291< 10.0.19045.7291< 10.0.22631.7079< 10.0.26100.8390< 10.0.26200.8390< 10.0.28000.2113CVSS 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 checksWork through these to decide whether this CVE applies to you.
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Identify Windows version and build numberRun 'winver' or 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' to get the exact Windows version and build numberAffected if The installed version falls below any of these thresholds: Windows 10 1607 < 10.0.14393.9140, Windows 10 1809 < 10.0.17763.8755, Windows 10 21h2 < 10.0.19044.7291, Windows 10 22h2 < 10.0.19045.7291, Windows 11 23h2 < 10.0.22631.7079, Windows 11 24h2 < 10.0.26100.8390, Windows 11 25h2 < 10.0.26200.83
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Verify TCP/IP stack is enabledCheck network adapter status via 'Get-NetAdapter | Where-Object Status -eq "Up"' and confirm TCP/IP protocol is bound using 'Get-NetAdapterBinding -ComponentID ms_tcpip'Affected if TCP/IP stack is in use (which is the default configuration for connected Windows systems)
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Review Security event logs for privilege escalation indicatorsOpen Event Viewer, navigate to Windows Logs > Security, and look for Event ID 4688 (new process creation) or 4672 (special privileges assigned) with suspicious parent processes, or check for multiple failed logon attempts followed by successful privileged operationsAffected if Unusual process creation under SYSTEM or privileged accounts, or evidence of unauthorized privilege escalation attempts originating from local authenticated sessions
Your system is affected if it runs any of the listed Windows versions below the specified build numbers AND has the TCP/IP stack enabled, which is the default state on Windows systems.
Generated from the published advisory. Verify against your own configuration.
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 · scoped10.0.14393.914010.0.17763.875510.0.19044.7291
Apply Microsoft security updates for Windows TCP/IP when available; given the privilege escalation risk, prioritize patching affected systems and audit local user permissions in the interim.
Install the corresponding Windows cumulative security update (check MSRC for the specific KB article for your Windows version)
- Identify the current Windows build version by running 'winver' or 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"'
- Open Settings > Windows Update (or manually check for updates)
- Search for and install the latest cumulative security update for your Windows version
- Alternatively, manually download the security update from the Microsoft Update Catalog (catalog.update.microsoft.com) using the KB number for this CVE (check MSRC for the specific KB)
- After installation, verify the build number matches or exceeds the fixed version: Windows 10 1607 → 10.0.14393.9140, Windows 10 1809 → 10.0.17763.8755, Windows 10 21h2 → 10.0.19044.7291, Windows 10 22h2 → 10.0.19045.7291, Windows 11 23h2 → 10.0.22631.7079, Windows 11 24h2 → 10.0.26100.8390, Windows 11 25h2 → 10.0.26200.8390, Windows 11 26h1 → 10.0.28000.2113
- Restart the system when prompted to complete the patch installation
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation4.0 h
- Testing6.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-34351 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-34351 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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