dbcve.org
Windows 10 1507Operating system · Microsoft

CVE-2025-54099

HIGH · 7.0 CVSS v3.1 Published 2025-09-09
Fix available
A fix is available. Upgrade to 10.0.10240.21128 / 10.0.14393.8422 or later.
See remediation →
72/100
Remediation priority · Elevated
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
Stack-based buffer overflow in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.

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 · high confidence

A stack-based buffer overflow exists in the Windows Ancillary Function Driver (AFD.sys), which handles WinSock network communications. A local, authorized attacker can exploit this overflow to execute code with elevated privileges, potentially achieving SYSTEM-level access on the affected Windows system.

MitigationApply the relevant Microsoft Windows security update to patch the AFD.sys driver. As this is a local privilege escalation vulnerability, prioritize patching systems with privileged user access and ensure standard user accounts follow least-privilege principles.

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:< 10.0.10240.21128
Windows 10 1607Operating system
Affected:< 10.0.14393.8422
Windows 10 1809Operating system
Affected:< 10.0.17763.7792
Windows 10 21h2Operating system
Affected:< 10.0.19044.6332
Windows 10 22h2Operating system
Affected:< 10.0.19045.6332
Windows 11 22h2Operating system
Affected:< 10.0.22621.5909
Windows 11 23h2Operating system
Affected:< 10.0.22631.5909
Windows 11 24h2Operating system
Affected:< 10.0.26100.6508

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
Local
Complexity
High
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

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

  1. Check Windows version and build number
    Run 'winver' or 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' to obtain the installed Windows build. Compare the build number to the affected version ranges: Windows 10 1507 must be <10.0.10240.21128, 1607 must be <10.0.14393.8422, 1809 must be <10.0.17763.7792, 21h2 must be <10.0.19044.6332, 22h2 must be <10.0.19045.6332; Windows 11 22h2 must be <10.0.22621.5909, 23h2 must be <10.0.22631.5909, 24h2 must be <10.0.26100.6508.
    Affected if The installed build number falls below any of the threshold builds listed for the corresponding Windows version.
  2. Verify AFD.sys driver file version
    Locate AFD.sys in the system32\drivers folder (typically C:\Windows\System32\drivers\AFD.sys), right-click and select Properties, then check the File Version field. Alternatively, run 'driverquery /v | findstr AFD' to query the driver module.
    Affected if The AFD.sys file version corresponds to a Windows build that is below the patched versions listed in the affected ranges.
  3. Confirm security update installation status
    Run 'powershell "Get-HotFix | Where-Object {$_.Description -like '*Security*'} | Sort-Object InstalledOn -Descending | Select-Object -First 5" to list recently installed security updates, or check Windows Update history for the specific security patch addressing this vulnerability.
    Affected if The specific security update for CVE-2025-54099 is not installed, and the system build remains in the vulnerable range.

The system is affected if it runs any Windows 10 or Windows 11 version with a build number lower than the threshold for its respective release, and the corresponding security update is not installed.

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 10.0.10240.21128 / 10.0.14393.8422 / 10.0.17763.7792 or later
Fixed in 10.0.10240.2112810.0.14393.842210.0.17763.7792
Interim mitigation

Apply the relevant Microsoft Windows security update to patch the AFD.sys driver. As this is a local privilege escalation vulnerability, prioritize patching systems with privileged user access and ensure standard user accounts follow least-privilege principles.

Recommended fix High confidence

Windows 10 1507: 10.0.10240.21128+ | Windows 10 1607: 10.0.14393.8422+ | Windows 10 1809: 10.0.17763.7792+ | Windows 10 21h2: 10.0.19044.6332+ | Windows 10 22h2: 10.0.19045.6332+ | Windows 11 22h2: 10.0.22621.5909+ | Windows 11 23h2: 10.0.22631.5909+ | Windows 11 24h2: 10.0.26100.6508+

  1. 1. Open Windows Settings on the affected system
  2. 2. Navigate to Windows Update (Settings > Update & Security > Windows Update)
  3. 3. Click 'Check for updates' to fetch the latest security patches
  4. 4. Install all available updates, particularly the security update containing the fix for CVE-2025-54099
  5. 5. Restart the system when prompted to complete the installation
  6. 6. Verify the installed build version matches or exceeds the fixed version for your Windows release
Caveat Standard Windows update applies cumulative patches; ensure compatibility testing for mission-critical systems before deploying

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

Fix this in Windows 10 1507 Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
13.0 hours of engineering $2,280
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Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2025-54099 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

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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-2025-54099 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