CVE-2025-33071
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 after free in Windows KDC Proxy Service (KPSSVC) allows an unauthorized attacker to execute code over a network.
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 confidenceUse-after-free vulnerability in Windows KDC Proxy Service (KPSSVC) allows an unauthenticated remote attacker to execute arbitrary code. The vulnerability stems from improper memory management in the service, where memory references are used after being freed, leading to potential code execution in the attacker's context.
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 dataall versions= r2< 10.0.14393.8148< 10.0.17763.7434< 10.0.20348.3745< 10.0.25398.1665< 10.0.26100.4270CVSS 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
- High
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:H/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 checksWork through these to decide whether this CVE applies to you.
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Verify if KDC Proxy Service (KPSSVC) is presentOpen Services console (services.msc) or run 'Get-Service -Name KPSSVC' in PowerShell to check if the KDC Proxy Service exists on the systemAffected if The KPSSVC service is installed and present on the system
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Determine if KPSSVC is runningCheck the service status via 'Get-Service -Name KPSSVC' or in Services console - note whether the service is Started or StoppedAffected if KPSSVC is currently running (even if disabled, an attacker needs the service to be present and exploitable)
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Identify Windows Server versionRun 'winver' or execute 'Get-ComputerInfo | Select-Object OsName, OsVersion, OsBuildNumber' in PowerShell to obtain the exact Windows Server build numberAffected if The build number falls within the affected ranges: Server 2016 < 10.0.14393.8148, Server 2019 < 10.0.17763.7434, Server 2022 < 10.0.20348.3745, Server 2022 23h2 < 10.0.25398.1665, Server 2025 < 10.0.26100.4270, or Server 2012/2012 R2 (all versions)
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Check KDC Proxy configurationInspect registry key HKLM\Software\Microsoft\KPSSP\Parameters\ or check for KDC proxy configuration in AD Sites and Services if the server is domain-joinedAffected if KDC Proxy is configured and enabled on the server (vulnerability requires the proxy feature to be set up)
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Verify listening ports for KPSSVCRun 'netstat -ano | findstr :4648' or use 'Get-NetTCPConnection -LocalPort 4648' to check if the KDC Proxy service is listening on port 4648Affected if Port 4648 is open and listening, indicating KPSSVC is actively accepting connections
System is likely affected if running a vulnerable Windows Server version (2012 through 2025 per the version thresholds) AND the KPSSVC service is present and configured, even if currently stopped.
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 · scoped10.0.14393.814810.0.17763.743410.0.20348.3745
Apply Microsoft security updates addressing CVE-2025-33071 promptly. If immediate patching is not feasible, evaluate disabling KPSSVC if not required in the environment, or implement network-level access controls to limit exposure to trusted networks only.
Apply Microsoft security patch for CVE-2025-33071; target builds: Windows Server 2016 10.0.14393.8148+, Windows Server 2019 10.0.17763.7434+, Windows Server 2022 10.0.20348.3745+, Windows Server 2022 23h2 10.0.25398.1665+, Windows Server 2025 10.0.26100.4270+
- Check current Windows Server version by running `winver` or `Get-ComputerInfo | Select-Object OsVersion, OsBuildNumber`
- Open Windows Update by running `ms-settings:windowsupdate` or access via Control Panel
- Click 'Check for updates' and install all available security updates
- If the specific KB patch for CVE-2025-33071 is listed, ensure it is selected for installation
- After installation, restart the server if prompted
- Verify the fix by checking the OS build number matches or exceeds: Windows Server 2016 >= 10.0.14393.8148, Windows Server 2019 >= 10.0.17763.7434, Windows Server 2022 >= 10.0.20348.3745, Windows Server 2022 23h2 >= 10.0.25398.1665, Windows Server 2025 >= 10.0.26100.4270
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA3.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-33071 — 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-2025-33071 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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