dbcve.org
Windows 10 1507Operating system · Microsoft

CVE-2025-49661

HIGH · 7.8 CVSS v3.1 Published 2025-07-08
Fix available
A fix is available. Upgrade to 10.0.10240.21073 / 10.0.14393.8246 or later.
See remediation →
80/100
Remediation priority · High
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
Untrusted pointer dereference 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

This is a local privilege escalation vulnerability in the Windows Ancillary Function Driver (afd.sys), which handles Winsock API calls. The untrusted pointer dereference flaw allows an authorized local attacker to elevate their privileges to SYSTEM level.

MitigationApply the Microsoft security update for CVE-2025-49661 via Windows Update or manual patch deployment. Test network connectivity and socket operations after patching to ensure the AFD driver functions correctly.

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:< 10.0.10240.21073
Windows 10 1607Operating system
Affected:< 10.0.14393.8246
Windows 10 1809Operating system
Affected:< 10.0.17763.7558
Windows 10 21h2Operating system
Affected:< 10.0.19044.6093
Windows 10 22h2Operating system
Affected:< 10.0.19045.6093
Windows 11 22h2Operating system
Affected:< 10.0.22621.5624
Windows 11 23h2Operating system
Affected:< 10.0.22631.5624
Windows 11 24h2Operating system
Affected:< 10.0.26100.4652

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

CVSS:3.1/AV:L/AC:L/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 build version
    Run 'winver' from command prompt or check System Properties, or run 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"'
    Affected if Build number is below the fixed versions for your Windows release (see version-specific thresholds below)
  2. Identify exact Windows release
    Run 'ver' or check winver output to determine if you are on Windows 10 1507, 1607, 1809, 21h2, 22h2, or Windows 11 22h2, 23h2, or 24h2
    Affected if The detected release matches any of the affected products listed in the CVE
  3. Compare build against fixed versions
    Document your exact build number (e.g., 10.0.19045.6093 for Win10 22h2) and compare against the CVE fixed versions: Win10 1507 < 10.0.10240.21073, Win10 1607 < 10.0.14393.8246, Win10 1809 < 10.0.17763.7558, Win10 21h2 < 10.0.19044.6093, Win10 22h2 < 10.0.19045.6093, Win11 22h2 < 10.0.22621.5624, Win11 23h2 < 10.0.22631.5624, Win11 24h2 < 10.0.26100.4652
    Affected if Your installed build number is lower than the corresponding fixed build for your Windows release
  4. Optional: Verify afd.sys version
    Navigate to C:\Windows\System32\drivers\afd.sys, right-click Properties, and check the File Version tab
    Affected if The afd.sys version corresponds to a build older than the fixed versions (lesser certainty check, version matching is approximate)

If your Windows build number is lower than the threshold for your specific Windows release (10 or 11 version/edition), the afd.sys driver is vulnerable and allows local privilege escalation to SYSTEM.

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 10.0.10240.21073 / 10.0.14393.8246 / 10.0.17763.7558 or later
Fixed in 10.0.10240.2107310.0.14393.824610.0.17763.7558
Interim mitigation

Apply the Microsoft security update for CVE-2025-49661 via Windows Update or manual patch deployment. Test network connectivity and socket operations after patching to ensure the AFD driver functions correctly.

Recommended fix High confidence

Windows 10 1507: 10.0.10240.21073 or later | Windows 10 1607: 10.0.14393.8246 or later | Windows 10 1809: 10.0.17763.7558 or later | Windows 10 21h2: 10.0.19044.6093 or later | Windows 10 22h2: 10.0.19045.6093 or later | Windows 11 22h2: 10.0.22621.5624 or later | Windows 11 23h2: 10.0.22631.5624 or

  1. Open Settings > System > Windows Update and check for updates
  2. Install all pending Windows updates, particularly any Security Update released after the CVE disclosure date
  3. Alternatively, manually verify your current Windows version by running 'winver' and ensure it matches or exceeds the fixed version for your Windows release
  4. For enterprise environments, deploy the appropriate Windows Security Update (KB) through your patch management system
Caveat Standard Windows update; no breaking changes expected for typical end users. Ensure backup of critical data before applying updates as a best practice.

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
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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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-2025-49661 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