CVE-2026-26173

Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability

HIGH 7.0

At a glance

Source: NVD
EPSS: EPSS 0.16 % · percentile 5 (2026-10-28)
State: PUBLISHED
Published: 2026-04-14 16:58 UTC
Updated: 2026-10-15 15:53 UTC
Assigner: microsoft
NVD status: Analyzed

Description

Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.

Weaknesses (CWE)

CWE-362 — Race Condition
CWE-416 — Use After Free
CWE-476 — NULL Pointer Dereference

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-26173

Scores

Version	Score	Vector	Scored by
CVSS 3.1	HIGH 7.0	CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C	microsoft
CVSS 3.1	HIGH 7.0	CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H	NVD · secure@microsoft.com (Secondary)

European references

ENISA EUVD · EUVD-2026-22408
GCVE · GCVE-0-2026-26173

CERT-FR advisories

CERTFR-2026-AVI-0442 — Multiples vulnérabilités dans Microsoft Windows · cert.ssi.gouv.fr

Affected configurations (NVD CPE)

cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x64:* < 10.0.14393.9060
cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x86:* < 10.0.14393.9060
cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x64:* < 10.0.17763.8644
cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x86:* < 10.0.17763.8644
cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:arm64:* < 10.0.19044.7184
cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:x64:* < 10.0.19044.7184
cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:x86:* < 10.0.19044.7184
cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:arm64:* < 10.0.19045.7184
cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:x64:* < 10.0.19045.7184
cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:x86:* < 10.0.19045.7184
cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:arm64:* < 10.0.22631.6936
cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:x64:* < 10.0.22631.6936
cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:arm64:* < 10.0.26100.8246
cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:x64:* < 10.0.26100.8246
cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:arm64:* < 10.0.26200.8246
cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:x64:* < 10.0.26200.8246
cpe:2.3:o:microsoft:windows_11_26h1:*:*:*:*:*:*:arm64:* < 10.0.28000.1836
cpe:2.3:o:microsoft:windows_11_26h1:*:*:*:*:*:*:x64:* < 10.0.28000.1836
cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2016:*:*:*:*:*:*:*:* < 10.0.14393.9060
cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:* < 10.0.17763.8644
cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:*:* < 10.0.20348.5020
cpe:2.3:o:microsoft:windows_server_2022_23h2:*:*:*:*:*:*:*:* < 10.0.25398.2274
cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:*:* < 10.0.26100.32690

Affected products

Product	Versions
Microsoft · Windows 10 Version 1607	affected 10.0.14393.0 < 10.0.14393.9060
Microsoft · Windows 10 Version 1809	affected 10.0.17763.0 < 10.0.17763.8644
Microsoft · Windows 10 Version 21H2	affected 10.0.19044.0 < 10.0.19044.7184
Microsoft · Windows 10 Version 22H2	affected 10.0.19045.0 < 10.0.19045.7184
Microsoft · Windows 11 version 23H2	affected 10.0.22631.0 < 10.0.22631.6936
Microsoft · Windows 11 Version 23H2	affected 10.0.22631.0 < 10.0.22631.6936
Microsoft · Windows 11 Version 24H2	affected 10.0.26100.0 < 10.0.26100.8246
Microsoft · Windows 11 Version 25H2	affected 10.0.26200.0 < 10.0.26200.8246
Microsoft · Windows 11 version 26H1	affected 10.0.28000.0 < 10.0.28000.1836
Microsoft · Windows Server 2012	affected 6.2.9200.0 < 6.2.9200.26026
Microsoft · Windows Server 2012 (Server Core installation)	affected 6.2.9200.0 < 6.2.9200.26026
Microsoft · Windows Server 2012 R2	affected 6.3.9600.0 < 6.3.9600.23132
Microsoft · Windows Server 2012 R2 (Server Core installation)	affected 6.3.9600.0 < 6.3.9600.23132
Microsoft · Windows Server 2016	affected 10.0.14393.0 < 10.0.14393.9060
Microsoft · Windows Server 2016 (Server Core installation)	affected 10.0.14393.0 < 10.0.14393.9060
Microsoft · Windows Server 2019	affected 10.0.17763.0 < 10.0.17763.8644
Microsoft · Windows Server 2019 (Server Core installation)	affected 10.0.17763.0 < 10.0.17763.8644
Microsoft · Windows Server 2022	affected 10.0.20348.0 < 10.0.20348.5020
Microsoft · Windows Server 2022, 23H2 Edition (Server Core installation)	affected 10.0.25398.0 < 10.0.25398.2274
Microsoft · Windows Server 2025	affected 10.0.26100.0 < 10.0.26100.32690

Sources

Source	Licence
CVE List (CVEProject cvelistV5)	CVE Program Terms of Use
EPSS (FIRST.org)	FIRST — attribution requested
ENISA EUVD	ENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)	Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feeds	Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD