CVE-2026-45634
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 · uneditedOut-of-bounds read in Windows DHCP Server allows an authorized attacker to disclose information 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 · high confidenceAn out-of-bounds read vulnerability exists in Windows DHCP Server where the service reads memory outside allocated buffer boundaries. This memory safety flaw allows a locally authenticated, authorized attacker to potentially read sensitive information from server memory that should not be accessible.
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< 10.0.14393.9234< 10.0.17763.8880< 10.0.19044.7417< 10.0.19045.7417< 10.0.22631.7219< 10.0.26100.8655< 10.0.26200.8655< 10.0.28000.2269CVSS 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
- None
- Availability
- None
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
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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Verify DHCP Server role is installedRun 'Get-WindowsFeature -Name DHCP' in PowerShell (Server) or check 'Services for Network Applications' in Windows Features (Client). Alternatively, check for the DHCP Server service via 'Get-Service -Name DHCPServer' in PowerShell.Affected if DHCP Server role is not installed - the vulnerability does not apply
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Confirm DHCP Server service is runningRun 'Get-Service -Name DHCPServer' in PowerShell. Check that the Status is 'Running'.Affected if Service is not running - the vulnerable code path may not be active
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Identify installed Windows build versionRun 'winver' from Run dialog, or 'systeminfo | findstr /B /C:"OS"' from command prompt, or '[System.Environment]::OSVersion.Version' in PowerShell. Note the full build number (e.g., 10.0.19045.7417).Affected if Version cannot be determined or is not in the listed Windows 10/11 product families
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Compare build against affected version rangesMatch your Windows build number to the following: 1607 (<10.0.14393.9234), 1809 (<10.0.17763.8880), 21h2 (<10.0.19044.7417), 22h2 (<10.0.19045.7417), 23h2 (<10.0.22631.7219), 24h2 (<10.0.26100.8655), 25h2 (<10.0.26200.8655), 26h1 (<10.0.28000.2269).Affected if Your build number falls below the patched version for your Windows release - you are potentially affected
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Confirm DHCP Server authorization (if domain-joined)In Active Directory environments, verify DHCP server authorization status via 'Get-DhcpServerInDC' in PowerShell on a DHCP server, or check the DHCP console for authorization status.Affected if DHCP Server is authorized on the domain - an authorized attacker could potentially trigger the vulnerable code path
You are affected if DHCP Server role is installed/running AND your Windows build version is below the patched threshold for your specific Windows release (10/11).
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 · scoped10.0.14393.923410.0.17763.888010.0.19044.7417
Apply available Microsoft security updates for Windows DHCP Server. Until a patch is released, limit local access to the DHCP server to trusted, authorized administrators only and monitor for unusual access patterns.
Apply Microsoft security update KBxxxxx (check msrc.microsoft.com for specific KB article for this CVE) to reach version 10.0.14393.9234 (Win10 1607), 10.0.17763.8880 (Win10 1809), 10.0.19044.7417 (Win10 21h2), 10.0.19045.7417 (Win10 22h2), 10.0.22631.7219 (Win11 23h2), 10.0.26100.8655 (Win11 24h2),
- Check current Windows version by running 'winver' or 'systeminfo' in Command Prompt
- Identify the specific Windows 10/11 version and build number from the list of affected versions
- Apply the Microsoft security update for CVE-2026-45634 through Windows Update or Microsoft Update Catalog
- Verify the update was installed by checking the installed updates via 'appwiz.cpl' -> 'View installed updates'
- Confirm the build number meets or exceeds the fixed version for your Windows release
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation2.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,752.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-45634 — 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-2026-45634 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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- 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