VDB

CVE-2026-21238

CVE-2026-21238 PUBLISHED CVSS 7.8 HIGH

Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability

Reported by microsoft · Published February 10, 2026

Improper access control in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.

Fixed versions

Upgrade to a fixed version or later. Language registries are listed first, then Linux distributions, then vendor products.

PackageEcosystemFixed in
Windows 11 Version 24H2Microsoft10.0.26100.7840

Risk scores

CVSS 3.1
7.8
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

Affected products

VendorProductVersions
MicrosoftWindows 10 Version 160710.0.14393.0
MicrosoftWindows 10 Version 180910.0.17763.0
MicrosoftWindows 10 Version 21H210.0.19044.0
MicrosoftWindows 10 Version 22H210.0.19045.0
MicrosoftWindows 11 version 22H310.0.22631.0
MicrosoftWindows 11 Version 23H210.0.22631.0
MicrosoftWindows 11 Version 24H210.0.26100.0
MicrosoftWindows 11 Version 25H210.0.26200.0
MicrosoftWindows 11 version 26H110.0.28000.0
MicrosoftWindows 11 Version 26H110.0.28000.0
MicrosoftWindows Server 20126.2.9200.0
MicrosoftWindows Server 2012 (Server Core installation)6.2.9200.0
MicrosoftWindows Server 2012 R26.3.9600.0
MicrosoftWindows Server 2012 R2 (Server Core installation)6.3.9600.0
MicrosoftWindows Server 201610.0.14393.0
MicrosoftWindows Server 2016 (Server Core installation)10.0.14393.0
MicrosoftWindows Server 201910.0.17763.0
MicrosoftWindows Server 2019 (Server Core installation)10.0.17763.0
MicrosoftWindows Server 202210.0.20348.0
MicrosoftWindows Server 2022, 23H2 Edition (Server Core installation)10.0.25398.0

…and 39 more

Timeline

  • Feb 10, 2026 CVE Published
  • Feb 10, 2026 PoC Published (137 in total, the first dated here)
  • Feb 11, 2026 EPSS Score (30 in total, the first dated here)
  • Feb 22, 2026 CVE Updated
  • Mar 17, 2026 Security Advisory (6 in total, the first dated here)
  • Mar 25, 2026 Coalition ESS Score (2 in total, the first dated here)

Query this with the API

The same record, from the CLI:

vulnetix vdb vuln CVE-2026-21238
vulnetix vdb fixes CVE-2026-21238

Or with curl, using the org id and key from your account page:

curl -s -H "Authorization: ApiKey ${VULNETIX_ORG_ID}:${VULNETIX_API_KEY}" \
  "https://api.vdb.vulnetix.com/v2/vuln/CVE-2026-21238/fixes/registry"

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References

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