dbcve.org
Windows 10 1607Operating system · Microsoft

CVE-2026-49181

CRITICAL · 9.8 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 →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click Patch available 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
Integer underflow (wrap or wraparound) in Windows DHCP Client allows an unauthorized attacker to elevate privileges over a network.

In the news

Third-party coverage
Trending covered by 1 outlet this week · latest 1w 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

Integer underflow vulnerability in Windows DHCP Client allows an unauthenticated attacker to achieve privilege elevation via network-based exploitation. The integer underflow (wraparound) likely occurs during DHCP response processing, potentially allowing crafted packets to corrupt memory and execute code with elevated privileges.

MitigationApply Microsoft security updates for Windows DHCP Client immediately; network segmentation and DHCP packet filtering can provide interim defense-in-depth until patches are deployed.

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 Server 2012Operating system
Affected:all versions= r2
Windows Server 2016Operating system
Affected:< 10.0.14393.9339
Windows Server 2019Operating system
Affected:< 10.0.17763.9020
Windows Server 2022Operating system
Affected:< 10.0.20348.5386
Windows Server 2025Operating system
Affected:< 10.0.26100.33158

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
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/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
    Run 'winver' or 'systeminfo' from command prompt, or check registry key 'HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion' for 'CurrentBuild' and 'DisplayVersion' values
    Affected if The build number is lower than the fixed version for your Windows release: 14393.9339 (1607/Server 2016), 17763.9020 (1809/Server 2019), 20348.5386 (Server 2022), or 26100.33158 (Server 2025); or if running Windows Server 2012/2012 R2 of any version
  2. Confirm DHCP Client service is running
    Run 'sc query dhcp' from command prompt or 'Get-Service Dhcp' from PowerShell. The service name is 'Dhcp'
    Affected if The service state shows 'RUNNING' - the DHCP Client must be active for the vulnerability to be exploitable
  3. Identify installed security updates
    Run 'Get-HotFix | Sort-Object InstalledOn -Descending | Select-Object -First 10' in PowerShell, or 'wmic qfe list' to list recent patches
    Affected if No security update matching the CVE (typically released in Microsoft Patch Tuesday) is installed for the DHCP Client component

You are affected if your Windows version falls within the affected ranges AND the DHCP Client service is running AND the corresponding security patch is not installed.

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 / 10.0.20348.5386 or later
Fixed in 10.0.14393.933910.0.17763.902010.0.20348.5386
Vendor patch msrc.microsoft.com →
Interim mitigation

Apply Microsoft security updates for Windows DHCP Client immediately; network segmentation and DHCP packet filtering can provide interim defense-in-depth until patches are deployed.

Recommended fix High confidence

Apply Microsoft security updates KBXXXXX (check MSRC for specific KB number for this CVE) to reach the minimum build versions specified

  1. Open Settings on the Windows system and navigate to Update & Security > Windows Update
  2. Click 'Check for updates' to retrieve the latest security patches from Microsoft Update
  3. Install all available security updates, specifically those addressing DHCP Client vulnerabilities
  4. Restart the system when prompted to complete the installation
  5. Verify the installed update by running 'winver' command or checking System Information to confirm the build number matches or exceeds: Windows 10 1607: 10.0.14393.9339 | Windows 10 1809: 10.0.17763.9020 | Windows Server 2016: 10.0.14393.9339 | Windows Server 2019: 10.0.17763.9020 | Windows Server 2022: 10.0.20348.5386 | Windows Server 2025: 10.0.26100.33158
  6. For Windows Server 2012 R2 (all versions), apply the latest cumulative update from Microsoft Update catalog to receive the security fix
Caveat Standard patching carries minimal risk; ensure backups exist and schedule maintenance window for production servers

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
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
16.0 hours of engineering $2,800
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,480.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2026-49181 — 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-2026-49181 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