CVE-2026-56168
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 · uneditedNull pointer dereference in Windows SMB Server allows an authorized attacker to deny service over a network.
In the news
Third-party coverage- Microsoft July 2026 Patch Tuesday fixes massive 570 flaws, 3 zero-days
- Microsoft CVE Summary - Bleeping Computer
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 confidenceA null pointer dereference vulnerability exists in Windows SMB Server that allows an authenticated attacker to crash the SMB service, causing a denial of service condition. The vulnerability is exploitable over the network and requires the attacker to have some level of authorized access to the SMB service.
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< 10.0.19044.7548< 10.0.19045.7548< 10.0.26100.8875< 10.0.26200.8875< 10.0.28000.2269< 10.0.28000.2525< 10.0.20348.5386< 10.0.26100.33158CVSS 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
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/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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Check Windows version and build numberOpen PowerShell and run: winver or systeminfo | findstr /B /C:"OS Name" /C:"OS Version". Alternatively, run 'Get-ComputerInfo | Select-Object WindowsVersion, OsBuildNumber, OsHardwareAbstractionLayer'Affected if The installed build number is lower than the affected version for your Windows release (19044.7548 for 21h2, 19045.7548 for 22h2, 26100.8875 for 11 24h2, 26200.8875 for 11 25h2, 28000.2269/28000.2525 for 11 26h1, 20348.5386 for Server 2022, 26100.33158 for Server 2025)
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Verify SMB Server service is runningOpen PowerShell and run: Get-Service -Name "Server" or Get-Service -Name "SmbServer"Affected if The SMB Server service (ServiceName: Server or SmbServer) is running and the version check in step 1 shows a build number below the affected threshold
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Confirm SMB is exposed on the networkRun: Get-SmbServerConfiguration | Select-Object -Property RequireSecuritySignature, EnableSMB1Protocol. Also check open ports with: Get-NetTCPConnection -LocalPort 445Affected if Port 445 (SMB) is listening and accessible, making the service exploitable over the network
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Check for recent security updates installedRun: Get-HotFix | Where-Object {$_.Description -eq "Security Update"} | Sort-Object InstalledOn -Descending | Select-Object -First 10. Look for updates dated after the CVE disclosureAffected if No recent SMB-related security updates are installed and the version check in step 1 shows a vulnerable build number
A system is affected if it runs any of the listed Windows versions with an SMB Server service enabled and the installed build number falls below the specified threshold for that Windows release.
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 · scoped10.0.19044.754810.0.19045.754810.0.20348.5386
Apply Microsoft security updates for Windows SMB Server when released. If immediate patching is not possible, consider network segmentation to limit SMB exposure and implement monitoring for service availability.
Windows KB5055523 (Cumulative Update) - install the appropriate version for your Windows edition and version
- Identify the current Windows version and build number by running 'winver' or 'systeminfo'
- For Windows 10 21h2: Install KB5055523 (Build 10.0.19044.7548) or later
- For Windows 10 22h2: Install KB5055523 (Build 10.0.19045.7548) or later
- For Windows 11 24h2: Install KB5055523 (Build 10.0.26100.8875) or later
- For Windows 11 25h2: Install KB5055523 (Build 10.0.26200.8875) or later
- For Windows 11 26h1: Install KB5055523 (Build 10.0.28000.2269 or 10.0.28000.2525) or later
- For Windows Server 2022: Install KB5055523 (Build 10.0.20348.5386) or later
- For Windows Server 2025: Install KB5055523 (Build 10.0.26100.33158) or later
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
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,808.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-56168 — 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-2026-56168 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
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