dbcve.org
Windows 11 22h2Operating system · Microsoft

CVE-2025-26651

MEDIUM · 6.5 CVSS v3.1 Published 2025-04-08
Fix available
A fix is available. Upgrade to 10.0.20348.3453 / 10.0.22621.5189 or later.
See remediation →
71/100
Remediation priority · Elevated
Remotely reachable 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
Exposed dangerous method or function in Windows Local Session Manager (LSM) allows an authorized 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

This vulnerability in Windows Local Session Manager (LSM) involves an exposed dangerous method or function that can be leveraged by an authorized attacker to cause a denial of service condition over a network. The LSM manages user sessions and terminal services, and the exposed functionality allows authenticated users to trigger a DoS state.

MitigationApply Microsoft security updates for CVE-2025-26651 once released. Prioritize patching systems with network-exposed LSM/Terminal Services interfaces.

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 11 22h2Operating system
Affected:< 10.0.22621.5189
Windows 11 23h2Operating system
Affected:< 10.0.22631.5189
Windows 11 24h2Operating system
Affected:< 10.0.26100.3775
Windows Server 2022Operating system
Affected:< 10.0.20348.3453
Windows Server 2022 23h2Operating system
Affected:< 10.0.25398.1551
Windows Server 2025Operating system
Affected:< 10.0.26100.3775

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
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 checks

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

  1. Check Windows build version
    Open Command Prompt and run 'winver' to display the OS version and build number, or run 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' to get detailed version info
    Affected if build number falls below any of these thresholds: 10.0.22621.5189 (Win11 22h2), 10.0.22631.5189 (Win11 23h2), 10.0.26100.3775 (Win11 24h2/Server 2025), 10.0.20348.3453 (Server 2022), 10.0.25398.1551 (Server 2022 23h2)
  2. Confirm Windows edition
    Run 'winver' or check System Properties to confirm whether the system is Windows 11 (consumer) or Windows Server variant, as the affected version ranges differ between client and server editions
    Affected if system is Windows 11 22h2, 23h2, or 24h2, or Windows Server 2022, 2022 23h2, or Windows Server 2025 with a build number below the corresponding threshold
  3. Verify Terminal Services/Remote Desktop status
    Open Services (services.msc) and check if 'Remote Desktop Services' (TermService) is running, or run 'reg query "HKLM\System\CurrentControlSet\Control\Terminal Server" /v fDenyTSConnections' - a value of 0 means RDP is enabled
    Affected if Terminal Services/Remote Desktop is enabled (fDenyTSConnections set to 0), exposing the LSM network interface to potential authenticated attackers

System is affected if it runs a Windows 11 or Windows Server version with a build number below the specified thresholds AND has Terminal Services/Remote Desktop enabled, allowing authenticated network attackers to trigger DoS via the exposed LSM functionality

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 10.0.20348.3453 / 10.0.22621.5189 / 10.0.22631.5189 or later
Fixed in 10.0.20348.345310.0.22621.518910.0.22631.5189
Interim mitigation

Apply Microsoft security updates for CVE-2025-26651 once released. Prioritize patching systems with network-exposed LSM/Terminal Services interfaces.

Recommended fix High confidence

Install Windows security update containing the fix for CVE-2025-26651 (build numbers: 10.0.22621.5189, 10.0.22631.5189, 10.0.26100.3775, 10.0.20348.3453, 10.0.25398.1551 depending on OS version)

  1. Open Settings on the Windows system and navigate to Windows Update
  2. Click 'Check for updates' to download and install the latest security updates
  3. Alternatively, manually download and install the specific KB (knowledge base) patch from Microsoft Update Catalog corresponding to this CVE
  4. Restart the system after installing the update to ensure the LSM component is fully patched
  5. Verify the installed update by running 'winver' or checking Windows Update history to confirm the build number matches or exceeds the fixed version for your Windows release
Caveat Standard Windows security update - minimal risk; patch is cumulative and should not disrupt services

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

Fix this in Windows 11 22h2 Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2025-26651 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2025-26651 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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