CVE-2026-20856 — Improper Input Validation in Microsoft Windows 10 Version 1607

CWE-20 — Improper Input Validation5 documents5 sources
Severity
8.1HIGHNVD
EPSS
0.1%
top 68.03%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
22
Microsoft Windows 10 Version 1607Microsoft Windows 10 Version 1809Microsoft Windows 10 Version 21h2+19 more
Timeline
PublishedJan 13

Description

Improper input validation in Windows Server Update Service allows an unauthorized attacker to execute code over a network.

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:HExploitability: 2.2 | Impact: 5.9

Affected Packages22 packages

▶CVEListV5microsoft/windows_server_20126.2.9200.0 — 6.2.9200.25868
▶CVEListV5microsoft/windows_server_201610.0.14393.0 — 10.0.14393.8783
▶CVEListV5microsoft/windows_server_201910.0.17763.0 — 10.0.17763.8276
▶CVEListV5microsoft/windows_server_202210.0.20348.0 — 10.0.20348.4648
▶CVEListV5microsoft/windows_server_202510.0.26100.0 — 10.0.26100.32230

🔴Vulnerability Details

2
GHSA
GHSA-gmj5-vp5f-rx2g: Improper input validation in Windows Server Update Service allows an unauthorized attacker to execute code over a network↗2026-01-13
▶
CVEList
Windows Server Update Service (WSUS) Remote Code Execution Vulnerability↗2026-01-13
▶

📋Vendor Advisories

1
Microsoft
Windows Server Update Service (WSUS) Remote Code Execution Vulnerability↗2026-01-13
▶

🕵️Threat Intelligence

1
Wiz
CVE-2026-20856 Impact, Exploitability, and Mitigation Steps | Wiz↗
▶
CVE-2026-20856 — Improper Input Validation in Microsoft | cvebase