CVE-2025-21418
HighExploitedPublic exploitWindows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability
Published Feb 11, 2025 · Updated Feb 26, 2026
Key Facts
Patch immediately- CVE-2025-21418 is a high-severity vulnerability (CVSS 7.8 v3.1) affecting Windows 10 1607 (Microsoft), Windows 10 1809 (Microsoft), Windows 10 21h2 (Microsoft) and 22 more products.
- It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Feb 11, 2025. Public exploit code is available.
- EPSS estimates a 1.6% probability of exploitation in the next 30 days.
- Fixed versions are available, including Windows 10 1607 10.0.10240.20915, Windows 10 1809 10.0.17763.6893, Windows 10 21h2 10.0.19044.5487.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
7.8
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
1.6%
Higher than 74.9% of all scored CVEs
Exploited in the wild
Yes
4 catalog listings
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2025-21418 brief as a PDF
Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.
Description
Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| CISA KEV | Feb 11, 2025 | Mar 4, 2025 | Not reported |
| Industry KEV feed | Feb 11, 2025 | Mar 4, 2025 | Not reported |
| CIRCL KEV | Feb 11, 2025 | Mar 4, 2025 | Not reported |
| ENISA EUVD | Feb 11, 2025 | n/a | Not reported |
Required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Affected Products
43 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Windows 10 1607Microsoft | See advisory | 10.0.10240.20915 |
| Windows 10 1809Microsoft | See advisory | 10.0.17763.6893 |
| Windows 10 21h2Microsoft | See advisory | 10.0.19044.5487 |
| Windows 10 22h2Microsoft | See advisory | 10.0.19045.5487 |
| Windows 11 22h2Microsoft | See advisory | 10.0.22621.4890 |
Patched Releases
Windows 10 1607
10.0.10240.20915
Windows 10 1809
10.0.17763.6893
Windows 10 21h2
10.0.19044.5487
Windows 10 22h2
10.0.19045.5487
Windows 11 22h2
10.0.22621.4890
Windows 11 23h2
10.0.22631.4890
Windows 11 24h2
10.0.26100.3107
Windows Server 2016
10.0.14393.7785
Windows Server 2019
10.0.17763.6893
Windows Server 2022
10.0.20348.3148, 10.0.20348.3207
Windows Server 2022 23h2
10.0.25398.1425
Windows Server 2025
10.0.26100.3107, 10.0.26100.3194
Windows 10 Version 1507
10.0.10240.20915
Windows 10 Version 1607
10.0.14393.7785
Windows 10 Version 1809
10.0.17763.6893
Windows 10 Version 21H2
10.0.19044.5487
Windows 10 Version 22H2
10.0.19045.5487
Windows 11 version 22H2
10.0.22621.4890
Windows 11 version 22H3
10.0.22631.4890
Windows 11 Version 23H2
10.0.22631.4890
Windows 11 Version 24H2
10.0.26100.3194
Windows Server 2008 R2 Service Pack 1
6.1.7601.27566
Windows Server 2008 R2 Service Pack 1 (Server Core installation)
6.1.7601.27566
Windows Server 2008 Service Pack 2
6.0.6003.23117
Windows Server 2008 Service Pack 2 (Server Core installation)
6.0.6003.23117
Timeline
Publicly disclosed
Feb 11, 2025
Added to CISA KEV
Feb 11, 2025
Added to Industry KEV feed
Feb 11, 2025
Added to CIRCL KEV
Feb 11, 2025
Added to ENISA EUVD
Feb 11, 2025
Last updated
Feb 26, 2026
Weakness Type
- CWE-122 Heap-based Buffer Overflow
References
- patchWindows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability
- exploitVulnCheck exploitation report
- exploitVulnCheck exploitation report
- exploitVulnCheck exploitation report
- exploitVulnCheck exploitation report
FAQ
Common Questions.
Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability
Affected: Windows 10 1607 (Microsoft); Windows 10 1809 (Microsoft); Windows 10 21h2 (Microsoft), among others. The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Feb 11, 2025.
Yes. It was added on Feb 11, 2025 with a federal remediation due date of Mar 4, 2025.
Public exploit code is available.
Fixed versions are available, including Windows 10 1607 10.0.10240.20915, Windows 10 1809 10.0.17763.6893, Windows 10 21h2 10.0.19044.5487.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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