CVE-2026-57976
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 Active Directory Domain Services 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 in Active Directory Domain Services allows an authenticated attacker to cause a denial of service by sending specially crafted network requests to the AD DS 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< 10.0.14393.9339< 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
- 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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Verify AD DS role is installedRun 'Get-WindowsFeature -Name AD-Domain-Services' in PowerShell on the target system. Alternatively, open Server Manager and check under 'Roles' for 'Active Directory Domain Services'.Affected if The AD DS role is not installed, the system is not affected by this specific vulnerability.
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Confirm the system is a Domain ControllerRun 'Get-ADDomainController -Filter *' or check system properties (sysdm.cpl) to see if the computer is a Domain Controller. The vulnerability resides in the AD DS service, which runs on DCs.Affected if The system is not a Domain Controller, the AD DS service is not running, and the vulnerability does not apply.
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Check installed Windows versionRun 'winver' from Run dialog, or run 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' in Command Prompt, or 'Get-ComputerInfo | select WindowsProductName, WindowsVersion' in PowerShell.Affected if The installed version falls within any of these ranges: Windows 10 1607 < 10.0.14393.9339, Windows 10 1809 < 10.0.17763.9020, Windows 10 21h2 < 10.0.19044.7548, Windows 10 22h2 < 10.0.19045.7548, Windows 11 24h2 < 10.0.26100.8875, Windows 11 25h2 < 10.0.26200.8875, Windows 11 26h1 < 10.0.28000.2525,
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Confirm AD DS network listeningRun 'netstat -ano | findstr "LDAP"' or check that port 389 (LDAP) is listening. The attacker sends network requests to the AD DS service, so the service must be bound to a network interface.Affected if LDAP ports are not listening, the AD DS service may not be exposed to network requests, reducing exploitability.
A system is affected if it is a Domain Controller with AD DS installed, running a Windows version listed in the affected ranges, and has LDAP network listeners active.
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 patches for Active Directory Domain Services when available. Ensure proper network segmentation and authentication controls are in place to limit exposure to authorized users only.
Install the latest cumulative update for your specific Windows version to obtain the fixed build number (10.0.14393.9339+ for Win10 1607, 10.0.17763.9020+ for Win10 1809, 10.0.19044.7548+ for Win10 21h2, 10.0.19045.7548+ for Win10 22h2, 10.0.26100.8875+ for Win11 24h2, 10.0.26200.8875+ for Win11 25h
- Identify the current Windows version and build number by running 'winver' or 'systeminfo'
- Determine which Windows 10 or 11 version is installed and check if the build number is below the fixed threshold for your version
- For Windows 10 1607: Upgrade to build 10.0.14393.9339 or later
- For Windows 10 1809: Upgrade to build 10.0.17763.9020 or later
- For Windows 10 21h2: Upgrade to build 10.0.19044.7548 or later
- For Windows 10 22h2: Upgrade to build 10.0.19045.7548 or later
- For Windows 11 24h2: Upgrade to build 10.0.26100.8875 or later
- For Windows 11 25h2: Upgrade to build 10.0.26200.8875 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
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-57976 — 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-2026-57976 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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