Is CVE-2025-21418 actively exploited?

Yes. KEV Intelligence tracks CVE-2025-21418 as a known exploited vulnerability. Confidence is confirmed.

What exploitation activity has KEV Intelligence observed?

KEV Intelligence has not yet recorded sensor-observed exploitation attempts for CVE-2025-21418. Our sensors continue to monitor for activity targeting this CVE.

Which versions are affected?

CVE-2025-21418 affects Microsoft Windows 10 Version 1507 and 25 other products. KEV Intelligence lists 25 version rows; examples include 10.0.10240.0 to < 10.0.10240.20915, 10.0.14393.0 to < 10.0.14393.7785, and 10.0.17763.0 to < 10.0.17763.6893.

Yes. CVE-2025-21418 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

CVE-2025-21418 Exploited in the Wild — Windows 10 Version 1507, Windows 10 Version 1607, Windows 10 Version 1809, Windows 10 Version 21H2, Windows 10 Version 22H2, Windows 11 version 22H2, Windows 11 version 22H3, Windows 11 Version 23H2, Windows 11 Version 24H2, Windows Server 2008 R2 Service Pack 1, Windows Server 2008 R2 Service Pack 1 (Server Core installation), Windows Server 2008 Service Pack 2, Windows Server 2008 Service Pack 2 (Server Core installation), Windows Server 2012, Windows Server 2012 (Server Core installation), Windows Server 2012 R2, Windows Server 2012 R2 (Server Core installation), Windows Server 2016, Windows Server 2016 (Server Core installation), Windows Server 2019, Windows Server 2019 (Server Core installation), Windows Server 2022, Windows Server 2022, 23H2 Edition (Server Core installation), Windows Server 2025, Windows Server 2025 (Server Core installation)

Q: What is CVE-2025-21418?

CVE-2025-21418 is a vulnerability affecting Microsoft Windows 10 Version 1507 and 25 other products. Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability

Q: How should organizations remediate it?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Q: Is it in CISA KEV?

Yes. CVE-2025-21418 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2025-21418 is a vulnerability affecting Microsoft Windows 10 Version 1507 and 25 other products. Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability

Is it exploited?

Yes. KEV Intelligence tracks this CVE as a known exploited vulnerability. Confidence is confirmed.

Who is affected?

Microsoft / Windows 10 Version 1507 affected before 10.0.10240.20915.

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability

Vendor Product Affected Status

Microsoft Windows 10 Version 1507 Before 10.0.10240.20915 Affected

Microsoft Windows 10 Version 1607 Before 10.0.14393.7785 Affected

Microsoft Windows 10 Version 1809 Before 10.0.17763.6893 Affected

Microsoft Windows 10 Version 21H2 Before 10.0.19044.5487 Affected

Microsoft Windows 10 Version 22H2 Before 10.0.19045.5487 Affected

Microsoft Windows 11 version 22H2 Before 10.0.22621.4890 Affected

Microsoft Windows 11 version 22H3 Before 10.0.22631.4890 Affected

Microsoft Windows 11 Version 23H2 Before 10.0.22631.4890 Affected

Microsoft Windows 11 Version 24H2 Before 10.0.26100.3194 Affected

Microsoft Windows Server 2008 R2 Service Pack 1 Before 6.1.7601.27566 Affected

Microsoft Windows Server 2008 R2 Service Pack 1 (Server Core installation) Before 6.1.7601.27566 Affected

Microsoft Windows Server 2008 Service Pack 2 Before 6.0.6003.23117 Affected

Microsoft Windows Server 2008 Service Pack 2 (Server Core installation) Before 6.0.6003.23117 Affected

Microsoft Windows Server 2012 Before 6.2.9200.25317 Affected

Microsoft Windows Server 2012 (Server Core installation) Before 6.2.9200.25317 Affected

Microsoft Windows Server 2012 R2 Before 6.3.9600.22417 Affected

Microsoft Windows Server 2012 R2 (Server Core installation) Before 6.3.9600.22417 Affected

Microsoft Windows Server 2016 Before 10.0.14393.7785 Affected

Microsoft Windows Server 2016 (Server Core installation) Before 10.0.14393.7785 Affected

Microsoft Windows Server 2019 Before 10.0.17763.6893 Affected

Microsoft Windows Server 2019 (Server Core installation) Before 10.0.17763.6893 Affected

Microsoft Windows Server 2022 Before 10.0.20348.3207 Affected

Microsoft Windows Server 2022, 23H2 Edition (Server Core installation) Before 10.0.25398.1425 Affected

Microsoft Windows Server 2025 Before 10.0.26100.3194 Affected

Microsoft Windows Server 2025 (Server Core installation) Before 10.0.26100.3194 Affected

View vendor advisory

Published: 11 Feb 2025
Exploitation Reported: 11 Feb 2025
Attack vector: Local
Complexity: Low
Privileges: Low
User interaction: None

CVE References

CVE Record CVE.org · CVE Record https://www.cve.org/CVERecord?id=CVE-2025-21418
Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability msrc.microsoft.com · Vendor Advisory https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21418

Exploitation evidence

Why KEV Intelligence marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

CISA

Recorded 11 Feb 2025

Independent exploitation attestation added to the KEV Intelligence record.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the KEV Intelligence Pro API.

Learn about Pro API access

Source	Added
CISA First	2025-02-11 00:00 UTC
Tenable Blog	2026-08-11 18:04 UTC

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets: 0
User-Agents: 0

Raw values available in Pro and Enterprise.

Scanner coverage

Nessus template detected 02 Jun 2025.

View Nessus template

Virtual patch status

No KEV Intelligence virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

Scanner Artifacts

Scanner and exploit-framework references linked to this CVE.

Scanner	Reference	Detected
Nessus	https://www.tenable.com/plugins/nessus/216140	02 Jun 2025

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

7.8 High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS

1.5%

Weaknesses

Heap-based Buffer Overflow CWE-122

Recent mention · Tenable Blog

Microsoft's August 2026 Patch Tuesday addresses 398 CVEs (CVE-2026-68820)

42Critical355Important1Moderate0LowMicrosoft addresses 398 CVEs in the eighth Patch Tuesday of 2026, with three zero-days, including one that was exploited in the wild.Microsoft patched 398 CVEs in its August 2026 Patch Tuesday release, with 42 rated critical, 355 rated as...

Read full advisory

All Mentions

Recent mention · Tenable Blog

Microsoft's August 2026 Patch Tuesday addresses 398 CVEs (CVE-2026-68820)

Tenable Blog · 11 Aug 2026

42Critical355Important1Moderate0LowMicrosoft addresses 398 CVEs in the eighth Patch Tuesday of 2026, with three zero-days, including one that was exploited in the wild.Microsoft patched 398 CVEs in its August 2026 Patch Tuesday release, with 42 rated critical, 355 rated as important and one rated as moderate. Our counts omitted two CVEs assigned by MITRE; CVE-2026-6726 and CVE-2026-6727.This month’s update includes patches for:.NET.NET Core.NET FrameworkAMD ZenActive Directory Certificate Services (AD CS)Application Information ServicesAzure Active DirectoryAzure CycleCloudAzure Monitor...

Recent mention · Tenable Blog

Microsoft's August 2026 Patch Tuesday Addresses 398 CVEs (CVE-2026-68820)

Tenable Blog · 11 Aug 2026

42Critical355Important1Moderate0LowMicrosoft addresses 398 CVEs in the eighth Patch Tuesday of 2026, with three zero-days, including one that was exploited in the wild.Microsoft patched 398 CVEs in its August 2026 Patch Tuesday release, with 42 rated critical, 355 rated as important and one rated as moderate. Our counts omitted two CVEs assigned by MITRE; CVE-2026-6726 and CVE-2026-6727.This month’s update includes patches for:.NET.NET Core.NET FrameworkAMD ZenActive Directory Certificate Services (AD CS)Application Information ServicesAzure Active DirectoryAzure CycleCloudAzure Monitor...

Timeline

From disclosure to observed exploitation

11 Aug 2026
KEV confirmed by Tenable Blog

Exploitation attested by an external source
02 Jun 2025
Nessus plugin available

Scanner coverage available
11 Feb 2025
CVE published

Vulnerability disclosed publicly
11 Feb 2025
Added to CISA KEV

Listed in the CISA Known Exploited Vulnerabilities catalog
11 Dec 2024
CVE ID reserved

Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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Evidence confidence and provenance
First-party sensor telemetry
PoC and scanner references
Affected versions and enrichment
Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2025-21418

Free JSON includes basic KEV fields

{
  "cve_id": "CVE-2025-21418",
  "confidence": "Confirmed",
  "cvss_score": 7.8,
  "cvss_estimated": false,
  "epss_score": 0.01537,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}

CVE-2025-21418

What security teams need to know first

Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability

Tags

CVE References

Why KEV Intelligence marks this CVE as exploited

Exploited in the wild

Known exploited vulnerability sources

Operational artifacts and observed signals

Observed signals

Scanner coverage

Virtual patch status

Scanner Artifacts

Severity, weaknesses, and research context

Weaknesses

Microsoft's August 2026 Patch Tuesday addresses 398 CVEs (CVE-2026-68820)

All Mentions

From disclosure to observed exploitation

KEV confirmed by Tenable Blog

Nessus plugin available

CVE published

Added to CISA KEV

CVE ID reserved

Automate this intelligence

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