CVE-2026-20810

Name: CVE-2026-20810
Creator: NVD / NIST
Published: 2026-01-13T18:16:07.547+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.8/10EPSS 0.47%

Last modified Jun 17, 2026

CVE-2026-20810 is a high-severity vulnerability rated 7.8/10 on the CVSS scale. Free of memory not on the heap in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.. EPSS estimates a 0.47% chance of exploitation in the next 30 days.

Description

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

Metrics

CVSS 3.1

7.8/10

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

EPSS Probability

0.47%

37.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-590

Affected Software

Vendor	Product	Versions
Microsoft	Windows 10 1809	< 10.0.17763.8276
Microsoft	Windows 10 21h2	< 10.0.19044.6809
Microsoft	Windows 10 22h2	< 10.0.19045.6809
Microsoft	Windows Server 2019	< 10.0.17763.8276

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20810Vendor Advisory

Timeline

Published: Jan 13, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is 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.

How severe is CVE-2026-20810?

CVE-2026-20810 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.47% probability of exploitation in the next 30 days.

How do I fix CVE-2026-20810?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-20810?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST