🛡️ CVE-2026-20810 — windows-10-1809

🟠 CVSS 7.8 — High ✅ No Known Exploit CWE-590 NVD
7.8
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

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

How this vulnerability can be exploited

This issue can be reached with local access to the system, attack complexity is low, an attacker needs low-level privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability high.

Weakness class

CVE-2026-20810 is classified as CWE-590: Free of Memory not on the Heap. The product calls free() on a pointer to memory that was not allocated using associated heap allocation functions such as malloc(), calloc(), or realloc().

Affected software

CVE-2026-20810 is recorded against 4 packages.

  • windows-10-1809 (fixed in 10.0.17763.8276)
  • windows-10-21h2 (fixed in 10.0.19044.6809)
  • windows-10-22h2 (fixed in 10.0.19045.6809)
  • windows-server-2019 (fixed in 10.0.17763.8276)

Timeline and source

Published on 13 January 2026 and last revised on 17 June 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

msrc.microsoft.com

Details

Severity HIGH
CVSS Score 7.8
CVSS Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE CWE-590
Public Exploit ✅ No
Source NVD
Published 2026-01-13
Updated 2026-08-11
Modified 2026-06-17
Fix URL N/A

Affected Packages

Software From version Fixed in
windows-10-1809 — 10.0.17763.8276
windows-10-21h2 — 10.0.19044.6809
windows-10-22h2 — 10.0.19045.6809
windows-server-2019 — 10.0.17763.8276

Similar Threats

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