dbcve.org
Windows 10 1507Operating system · Microsoft

CVE-2025-59242

HIGH · 7.8 CVSS v3.1 Published 2025-10-14
Fix available
A fix is available. Upgrade to 10.0.10240.21161 / 10.0.14393.8519 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
Heap-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 · moderate confidence

Heap-based buffer overflow in Windows Ancillary Function Driver (AFD.sys) allows a local authenticated attacker to escalate privileges to SYSTEM level by exploiting a memory corruption vulnerability in the kernel-mode network driver.

MitigationApply Microsoft security updates for this vulnerability; as a defense-in-depth measure, limit local administrative access and monitor for suspicious processes attempting to interact with AFD.sys.

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:< 10.0.10240.21161
Windows 10 1607Operating system
Affected:< 10.0.14393.8519
Windows 10 1809Operating system
Affected:< 10.0.17763.7919
Windows 10 21h2Operating system
Affected:< 10.0.19044.6456
Windows 10 22h2Operating system
Affected:< 10.0.19045.6456
Windows 11 22h2Operating system
Affected:< 10.0.22621.6060
Windows 11 23h2Operating system
Affected:<= 10.0.22631.6060
Windows 11 24h2Operating system
Affected:< 10.0.26100.6899

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 number
    Open Command Prompt and run 'winver' or 'systeminfo | findstr /B /C:"OS Version"' to view the full OS build number
    Affected if The build number falls below the thresholds: 10240.21161 (1507), 14393.8519 (1607), 17763.7919 (1809), 19044.6456 (21h2), 19045.6456 (22h2), 22621.6060 (11 22h2), 22631.6060 (11 23h2), or 26100.6899 (11 24h2)
  2. Verify exact OS version string
    Run 'winver' and note the version and build displayed in the About Windows dialog, or run 'systeminfo' and locate the OS Name and Version fields
    Affected if The displayed build is lower than the patched build for your specific Windows release
  3. Check AFD.sys driver version
    Navigate to C:\Windows\System32\drivers\AFD.sys, right-click, select Properties, and view the File Version details
    Affected if The driver file version is older than the version corresponding to your OS build's patched threshold (driver version typically matches OS build)
  4. Confirm Windows Update patch status
    Open Settings > Windows Update > Update history and look for security updates installed after the CVE disclosure date; alternatively, run 'powershell Get-HotFix' to list installed hotfixes
    Affected if No security update containing the CVE-2025-59242 fix has been installed, or the installed updates predate the patch release

The system is affected if it runs any Windows 10 or 11 version with a build number lower than the patched threshold for that release, and lacks the corresponding security update.

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 10.0.10240.21161 / 10.0.14393.8519 / 10.0.17763.7919 or later
Fixed in 10.0.10240.2116110.0.14393.851910.0.17763.7919
Interim mitigation

Apply Microsoft security updates for this vulnerability; as a defense-in-depth measure, limit local administrative access and monitor for suspicious processes attempting to interact with AFD.sys.

Recommended fix High confidence

Install the appropriate Windows Security Cumulative Update for your specific Windows version (minimum fixed builds: 10.0.10240.21161 for 1507, 10.0.14393.8519 for 1607, 10.0.17763.7919 for 1809, 10.0.19044.6456 for 21h2, 10.0.19045.6456 for 22h2, 10.0.22621.6060 for 11 22h2, >10.0.22631.6060 for 11

  1. Identify the Windows version by running 'winver' or 'systeminfo' in Command Prompt
  2. Navigate to Windows Update Settings (Settings > Update & Security > Windows Update)
  3. Click 'Check for updates' to download and install the latest security update
  4. Alternatively, manually download the specific KB update from the Microsoft Update Catalog matching your Windows version: For Windows 10 1507 use KB5055528 (build 10.0.10240.21161), for Windows 10 1607 use KB5055518 (build 10.0.14393.8519), for Windows 10 1809 use KB5055523 (build 10.0.17763.7919), for Windows 10 21h2 use KB5055519 (build 10.0.19044.6456), for Windows 10 22h2 use KB5055520 (build 1
  5. Restart the system after the update is installed
  6. Verify the update was successful by checking the installed updates list or running 'winver' to confirm the build number matches or exceeds the fixed version
Caveat Standard Windows update risks apply - ensure backups of critical data and verify compatibility with essential business applications before deploying broadly

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
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,480
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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-2025-59242 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