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Windows Server 2016Operating system · Microsoft

CVE-2025-26677

HIGH · 7.5 CVSS v3.1 Published 2025-05-13
Fix available
A fix is available. Upgrade to 10.0.14393.8066 / 10.0.17763.7314 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
Uncontrolled resource consumption in Remote Desktop Gateway Service 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

Uncontrolled resource consumption in Microsoft Remote Desktop Gateway Service allows an unauthenticated remote attacker to cause denial of service by exhausting server resources, likely through malformed or excessive RDP Gateway requests.

MitigationApply Microsoft security updates when available; until then, restrict network access to RD Gateway ports (default 443) via firewall or VPN, and monitor for unusual resource consumption patterns.

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 Server 2016Operating system
Affected:< 10.0.14393.8066
Windows Server 2019Operating system
Affected:< 10.0.17763.7314
Windows Server 2022Operating system
Affected:< 10.0.20348.3692
Windows Server 2022 23h2Operating system
Affected:< 10.0.25398.1611
Windows Server 2025Operating system
Affected:< 10.0.26100.4061

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. Verify Remote Desktop Gateway service is installed
    Open Services console (services.msc) and look for 'Remote Desktop Gateway' service, or run 'Get-Service -Name SessionEnv' in PowerShell
    Affected if the Remote Desktop Gateway service exists on the system
  2. Confirm the service is running
    In Services console, check the Status column for Remote Desktop Gateway, or run 'Get-Service -Name SessionEnv | Select-Object Status' in PowerShell
    Affected if the service is running or set to start automatically
  3. Check Windows Server build number
    Run 'winver' command or 'Get-ComputerInfo | Select-Object OsBuildNumber,OsVersion' in PowerShell to obtain the exact build number
    Affected if the build number is below the threshold for your Windows Server version (Server 2016: < 14393.8066, Server 2019: < 17763.7314, Server 2022: < 20348.3692, Server 2022 23h2: < 25398.1611, Server 2025: < 26100.4061)
  4. Verify network exposure of RD Gateway
    Check if port 443 (default RD Gateway port) is listening and exposed externally using 'netstat -an | findstr :443' or by reviewing firewall rules
    Affected if the RD Gateway port is accessible from untrusted networks

You are affected if Remote Desktop Gateway service is enabled and your Windows Server build number falls below the specified threshold for your version.

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 10.0.14393.8066 / 10.0.17763.7314 / 10.0.20348.3692 or later
Fixed in 10.0.14393.806610.0.17763.731410.0.20348.3692
Interim mitigation

Apply Microsoft security updates when available; until then, restrict network access to RD Gateway ports (default 443) via firewall or VPN, and monitor for unusual resource consumption patterns.

Recommended fix High confidence

Windows Server 2016 build 10.0.14393.8066 | Windows Server 2019 build 10.0.17763.7314 | Windows Server 2022 build 10.0.20348.3692 | Windows Server 2022 23h2 build 10.0.25398.1611 | Windows Server 2025 build 10.0.26100.4061

  1. Identify the current Windows Server version by running 'winver' or 'systeminfo' on the affected server
  2. Confirm the build number is below the fixed version for your Windows Server edition
  3. Apply the latest Windows cumulative update for your specific Windows Server version from Microsoft Update Catalog
  4. Alternatively, use Windows Update or Windows Server Update Services (WSUS) to deploy the security update
  5. Restart the server after applying the update to ensure the Remote Desktop Gateway Service is running the patched version
  6. Verify the fix by checking the installed updates and confirming the build number matches or exceeds 10.0.14393.8066 (Server 2016), 10.0.17763.7314 (Server 2019), 10.0.20348.3692 (Server 2022), 10.0.25398.1611 (Server 2022 23h2), or 10.0.26100.4061 (Server 2025)
Caveat Standard Windows update risks apply - ensure backups and test in staging before production deployment; some updates may require reboot

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

Fix this in Windows Server 2016 Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,970
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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-2025-26677 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