dbcve.org
Windows 10 1507Operating system · Microsoft

CVE-2025-33056

HIGH · 7.5 CVSS v3.1 Published 2025-06-10
Fix available
A fix is available. Upgrade to 10.0.10240.21034 / 10.0.14393.8148 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

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 · unedited
Improper access control in Microsoft Local Security Authority Server (lsasrv) allows an unauthorized attacker to deny service 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 confidence

A vulnerability in Microsoft Local Security Authority Server (lsasrv) involves improper access control that allows an unauthenticated remote attacker to cause a denial of service. The vulnerability resides in a core Windows security component responsible for authentication and policy enforcement.

MitigationApply Microsoft security updates for this vulnerability once released, as this is a core Windows OS component requiring vendor-supplied patches. Network segmentation and firewall rules can limit exposure until patches are applied.

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
Windows 10 1507Operating system
Affected:< 10.0.10240.21034
Windows 10 1607Operating system
Affected:< 10.0.14393.8148
Windows 10 1809Operating system
Affected:< 10.0.17763.7434
Windows 10 21h2Operating system
Affected:< 10.0.19044.5965
Windows 10 22h2Operating system
Affected:< 10.0.19045.5965
Windows 11 22h2Operating system
Affected:< 10.0.22621.5472
Windows 11 23h2Operating system
Affected:< 10.0.22631.5472
Windows 11 24h2Operating system
Affected:< 10.0.26100.4270

CVSS 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
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify Windows version
    Run 'winver' or 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' to determine the exact Windows version and build number
    Affected if The build number is below any of these thresholds: 10240.21034 (Win10 1507), 14393.8148 (Win10 1607), 17763.7434 (Win10 1809), 19044.5965 (Win10 21h2/22h2), 22621.5472 (Win11 22h2), 22631.5472 (Win11 23h2), or 26100.4270 (Win11 24h2)
  2. Check lsasrv.dll version
    Locate lsasrv.dll (typically in C:\Windows\System32) and view Properties > Details to see the File Version, or run 'powershell (Get-Item C:\Windows\System32\lsasrv.dll).VersionInfo'
    Affected if The file version is lower than the version bundled with the patched builds listed above for your Windows release
  3. Verify network exposure to LSA Server
    Check if ports 445 (SMB) or 139 (NetBIOS) are open to untrusted networks, or review firewall rules for inbound traffic to these ports using 'netsh advfirewall firewall show rule name=all'
    Affected if The LSA Server (lsasrv) is network-accessible without proper segmentation, as the vulnerability can be exploited remotely

If your Windows build number falls below the threshold for your specific version (10 1507 through 11 24h2) and the system is network-accessible, it is likely affected by this LSA Server denial of service vulnerability.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 · scoped
Upgrade available Upgrade to 10.0.10240.21034 / 10.0.14393.8148 / 10.0.17763.7434 or later
Fixed in 10.0.10240.2103410.0.14393.814810.0.17763.7434
Interim mitigation

Apply Microsoft security updates for this vulnerability once released, as this is a core Windows OS component requiring vendor-supplied patches. Network segmentation and firewall rules can limit exposure until patches are applied.

Recommended fix High confidence

Install the appropriate Windows security update for your version (e.g., KBxxxxxx) from Windows Update that addresses CVE-2025-33056

  1. Identify the current Windows version and build by running 'winver' or 'systeminfo' in Command Prompt
  2. Open Windows Settings and navigate to Windows Update (Settings > Update & Security > Windows Update)
  3. Click 'Check for updates' to download and install the latest security updates
  4. After installation, verify the build number matches or exceeds the fixed version for your Windows edition: Windows 10 1507 should be 10.0.10240.21034 or higher; Windows 10 1607 should be 10.0.14393.8148 or higher; Windows 10 1809 should be 10.0.17763.7434 or higher; Windows 10 21h2 should be 10.0.19044.5965 or higher; Windows 10 22h2 should be 10.0.19045.5965 or higher; Windows 11 22h2 should be 1
  5. Restart the system to complete the update installation
Caveat Standard Windows update; review release notes for any known issues before deploying in production environments

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Windows 10 1507 Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,176.

Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-33056 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • 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