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NVD / CVE Program· CNA microsoft

CVE-2025-21418: Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability

HighCVSS 7.8 · v3.1KEVWeaponized Fix available

Noroxi assessment

Priority: This week (action score 62/100)

  • CISA has confirmed exploitation in the wild (Feb 11, 2025). Remediation deadline for US federal agencies: Mar 4, 2025.
  • Probability of exploitation in the next 30 days: 2.1% (FIRST EPSS); higher than 82.2% of all records.
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Windows 10 for 32-bit Systems 10.0.10240.20915; Windows 10 for x64-based Systems 10.0.10240.20915; Windows 10 Version 1607 for 32-bit Systems 10.0.14393.7785.

Don’t wait for the next maintenance window. Upgrade to Windows 10 for 32-bit Systems 10.0.10240.20915; Windows 10 for x64-based Systems 10.0.10240.20915; Windows 10 Version 1607 for 32-bit Systems 10.0.14393.7785 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · CISA KEV · FIRST EPSS

Published
Feb 11, 2025
Updated
Jun 17, 2026
EPSS
2.1% · 82th percentile

Report tools

JSON

Action score

62

This week

Don’t wait for the next maintenance window.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
30 / 30 · Listed
EPSS
1 / 30 · 2.1%

CISA SSVC decision

Exploitation
active
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · microsoft
7.8
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Actively exploited in the wild

CISA added this to its Known Exploited Vulnerabilities catalog on Feb 11, 2025. That signals real attacks, not theory.

Remediation deadline for US federal agencies: Mar 4, 2025.

Get told when this record changes

  • In CISA KEV: exploitation in the wild confirmed
  • Weaponized exploit exists
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2025-21418

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
microsoftwindows 10 1607
microsoftwindows 10 1809
microsoftwindows 10 21h2
microsoftwindows 10 22h2
microsoftwindows 11 22h2
microsoftwindows 11 23h2
microsoftwindows 11 24h2
microsoftwindows server 2008
microsoftwindows server 2012
microsoftwindows server 2016
microsoftwindows server 2019
microsoftwindows server 2022

and 2 more

Versions reported by the vendor

Affected version ranges reported by the assigning authority (microsoft). Independent of NVD's CPE analysis and usually ahead of it.

  • Microsoft Windows 10 Version 1507

    • 10.0.10240.0 and later · before 10.0.10240.20915affected

  • Microsoft Windows 10 Version 1607

    • 10.0.14393.0 and later · before 10.0.14393.7785affected

  • Microsoft Windows 10 Version 1809

    • 10.0.17763.0 and later · before 10.0.17763.6893affected

  • Microsoft Windows 10 Version 21H2

    • 10.0.19044.0 and later · before 10.0.19044.5487affected

  • Microsoft Windows 10 Version 22H2

    • 10.0.19045.0 and later · before 10.0.19045.5487affected

  • Microsoft Windows 11 version 22H2

    • 10.0.22621.0 and later · before 10.0.22621.4890affected

  • Microsoft Windows 11 version 22H3

    • 10.0.22631.0 and later · before 10.0.22631.4890affected

  • Microsoft Windows 11 Version 23H2

    • 10.0.22631.0 and later · before 10.0.22631.4890affected

  • Microsoft Windows 11 Version 24H2

    • 10.0.26100.0 and later · before 10.0.26100.3194affected

  • Microsoft Windows Server 2008 R2 Service Pack 1

    • 6.1.7601.0 and later · before 6.1.7601.27566affected

  • Microsoft Windows Server 2008 R2 Service Pack 1 (Server Core installation)

    • 6.1.7601.0 and later · before 6.1.7601.27566affected

  • Microsoft Windows Server 2008 Service Pack 2

    • 6.0.6003.0 and later · before 6.0.6003.23117affected
Affected versions · NVD (9)

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • microsoft windows server 2008all versions
  • microsoft windows server 2008r2
  • microsoft windows server 2012all versions
  • microsoft windows server 2012r2
  • microsoft windows server 2016before 10.0.14393.7785
  • microsoft windows server 2019before 10.0.17763.6893
  • microsoft windows server 2022before 10.0.20348.3148
  • microsoft windows server 2022 23h2before 10.0.25398.1425
  • microsoft windows server 2025before 10.0.26100.3107

Same product

microsoft: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-33824Windows Internet Key Exchange (IKE) Service Extensions Remote Code Execution VulnerabilityKEV
    92Now
  • CVE-2018-8174A remote code execution vulnerability exists in the way that the VBScript engine handles objects in memory, aka "Windows VBScript Engine…KEV
    86Now
  • CVE-2026-21510Windows Shell Security Feature Bypass VulnerabilityKEV
    83Now

Published before and after this one in the same product

  • ← EarlierCVE-2025-21254Feb 11, 2025 · Internet Connection Sharing (ICS) Denial of Service Vulnerability
    26Monitor
  • ← EarlierCVE-2025-21351Feb 11, 2025 · Windows Active Directory Domain Services API Denial of Service Vulnerability
    31Monitor
  • Later →CVE-2025-24048Mar 11, 2025 · Windows Hyper-V Elevation of Privilege Vulnerability
    31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Windows 10 for 32-bit Systems10.0.10240.20915 · KB5052040Microsoft (MSRC)
Windows 10 for x64-based Systems10.0.10240.20915 · KB5052040Microsoft (MSRC)
Windows 10 Version 1607 for 32-bit Systems10.0.14393.7785 · KB5052006Microsoft (MSRC)
Windows 10 Version 1607 for x64-based Systems10.0.14393.7785 · KB5052006Microsoft (MSRC)
Windows 10 Version 1809 for 32-bit Systems10.0.17763.6893 · KB5052000Microsoft (MSRC)
Windows 10 Version 1809 for x64-based Systems10.0.17763.6893 · KB5052000Microsoft (MSRC)
Windows 10 Version 21H2 for 32-bit Systems10.0.19044.5487 · KB5051974Microsoft (MSRC)
Windows 10 Version 21H2 for ARM64-based Systems10.0.19044.5487 · KB5051974Microsoft (MSRC)
Windows 10 Version 21H2 for x64-based Systems10.0.19044.5487 · KB5051974Microsoft (MSRC)
Windows 10 Version 22H2 for 32-bit Systems10.0.19045.5487 · KB5051974Microsoft (MSRC)
Windows 10 Version 22H2 for ARM64-based Systems10.0.19045.5487 · KB5051974Microsoft (MSRC)
Windows 10 Version 22H2 for x64-based Systems10.0.19045.5487 · KB5051974Microsoft (MSRC)
Windows 11 Version 22H2 for ARM64-based Systems10.0.22621.4890 · KB5051989Microsoft (MSRC)
Windows 11 Version 22H2 for x64-based Systems10.0.22621.4890 · KB5051989Microsoft (MSRC)
Windows 11 Version 23H2 for ARM64-based Systems10.0.22631.4890 · KB5051989Microsoft (MSRC)
Windows 11 Version 23H2 for x64-based Systems10.0.22631.4890 · KB5051989Microsoft (MSRC)
Windows 11 Version 24H2 for ARM64-based Systems10.0.26100.3107 · KB5052105Microsoft (MSRC)
Windows 11 Version 24H2 for ARM64-based Systems10.0.26100.3194 · KB5051987Microsoft (MSRC)
Windows 11 Version 24H2 for x64-based Systems10.0.26100.3107 · KB5052105Microsoft (MSRC)
Windows 11 Version 24H2 for x64-based Systems10.0.26100.3194 · KB5051987Microsoft (MSRC)
Windows Server 2008 for 32-bit Systems Service Pack 26.0.6003.23117 · KB5052038Microsoft (MSRC)
Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation)6.0.6003.23117 · KB5052038Microsoft (MSRC)
Windows Server 2008 for x64-based Systems Service Pack 26.0.6003.23117 · KB5052038Microsoft (MSRC)
Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation)6.0.6003.23117 · KB5052038Microsoft (MSRC)
Windows Server 2008 R2 for x64-based Systems Service Pack 16.1.7601.27566 · KB5052016Microsoft (MSRC)
Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)6.1.7601.27566 · KB5052016Microsoft (MSRC)
Windows Server 20126.2.9200.25317 · KB5052020Microsoft (MSRC)
Windows Server 2012 (Server Core installation)6.2.9200.25317 · KB5052020Microsoft (MSRC)
Windows Server 2012 R26.3.9600.22417 · KB5052042Microsoft (MSRC)
Windows Server 2012 R2 (Server Core installation)6.3.9600.22417 · KB5052042Microsoft (MSRC)

+13

Exploit status

Weaponized

A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. CISA KEV-1 d
  2. Published
  3. TodayNov 14, 2026+640 d

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-122 · Heap-based Buffer Overflow

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

References

Show all references (1 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records