What is CVE-2026-20810?

CVE-2026-20810 is a high-severity vulnerability in Microsoft Windows 10 Version 1809, classified under CWE-590. CVSS score: 7.8/10. Published 2026-01-13.

How severe is CVE-2026-20810?

High severity. CVSS v3 base score is 7.8 out of 10.

Vulnerability in Microsoft Windows 10 Version 1809

CVE-2026-20810

Free of memory not on the heap in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.

EPSS: 0.001 (15.9th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.8 (High). Vector: 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

Microsoft Windows 10 Version 1809 — versions 10.0.17763.0
Microsoft Windows 10 Version 21h2 — versions 10.0.19044.0
Microsoft Windows 10 Version 22h2 — versions 10.0.19045.0
Microsoft Windows Server 2019 — versions 10.0.17763.0
Microsoft Windows Server 2019 (Server Core Installation) — versions 10.0.17763.0

Weakness classification (CWE)

CWE-590

References

Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability (vendor-advisory, patch)

Frequently asked questions

What is CVE-2026-20810?: CVE-2026-20810 is a high-severity vulnerability in Microsoft Windows 10 Version 1809, classified under CWE-590. CVSS score: 7.8/10. Published 2026-01-13.
How severe is CVE-2026-20810?: High severity. CVSS v3 base score is 7.8 out of 10.