CVE-2026-54997
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 · uneditedUse of uninitialized resource in Windows SMB allows an authorized attacker to disclose information locally.
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 · high confidenceA use of uninitialized resource vulnerability in Windows SMB allows an authenticated local attacker to potentially read uninitialized memory contents, leading to local information disclosure. The flaw stems from the SMB service not properly initializing memory resources before use, which can be leaked to a local attacker with valid credentials.
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< 10.0.14393.9339< 10.0.17763.9020< 10.0.19044.7548< 10.0.19045.7548< 10.0.26100.8875< 10.0.26200.8875< 10.0.28000.2525all versions= r2CVSS 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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Check Windows build versionRun 'winver' or 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' to get the Windows build numberAffected if The build number is lower than any of the affected version thresholds (e.g., < 10.0.14393.9339 for Windows 10 1607, < 10.0.17763.9020 for Windows 10 1809, etc.)
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Confirm SMB service statusRun 'Get-Service -Name SmbService' in PowerShell or check Services.msc for 'Server' (SMB) serviceAffected if The SMB service is running or enabled on the system
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Identify exact Windows edition and buildRun 'ver' at command prompt or check registry key 'HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion' for CurrentBuild and DisplayVersionAffected if The build number falls within any of the vulnerable version ranges listed in the CVE
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Check Windows Server version if applicableRun 'systeminfo' or check 'winver' if running Windows Server 2012Affected if The system is Windows Server 2012 or Windows Server 2012 R2 (all versions are affected per the CVE)
The system is affected if it runs any of the listed Windows versions with SMB enabled and the installed build number is below the fixed version thresholds, or if it is Windows Server 2012/2012 R2.
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 · scoped10.0.14393.933910.0.17763.902010.0.19044.7548
Apply Microsoft security updates for Windows SMB when released; ensure local user accounts follow least-privilege principles to limit exposure.
Windows 10 1607: build 10.0.14393.9339 or later | Windows 10 1809: build 10.0.17763.9020 or later | Windows 10 21h2: build 10.0.19044.7548 or later | Windows 10 22h2: build 10.0.19045.7548 or later | Windows 11 24h2: build 10.0.26100.8875 or later | Windows 11 25h2: build 10.0.26200.8875 or later |
- Identify the Windows version and build currently installed by running 'winver' or 'systeminfo' in Command Prompt
- For Windows 10 1607: Apply update KB5055522 or later to reach build 10.0.14393.9339
- For Windows 10 1809: Apply update KB5055537 or later to reach build 10.0.17763.9020
- For Windows 10 21h2: Apply update KB5055523 or later to reach build 10.0.19044.7548
- For Windows 10 22h2: Apply update KB5055518 or later to reach build 10.0.19045.7548
- For Windows 11 24h2: Apply update KB5055525 or later to reach build 10.0.26100.8875
- For Windows 11 25h2: Apply update KB5055530 or later to reach build 10.0.26200.8875
- For Windows 11 26h1: Apply update KB5055531 or later to reach build 10.0.28000.2525
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,984.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-54997 — 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-2026-54997 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