MSRC-CVE-2026-83499 — Windows Server Update Service Elevation of Privilege Vulnerability

Summary

Impact: Elevation of Privilege. Microsoft rating: Important. Not known to be exploited — Exploitation Less Likely. Customer action: Required.

Details

What privileges could be gained by an attacker who successfully exploited the vulnerability?
An attacker who successfully exploited this vulnerability could execute code in the security context of the “NT AUTHORITY\Network Service” account.

Security updates
10.0.17763.9376 — https://support.microsoft.com/help/5126651
10.0.20348.5761 — https://support.microsoft.com/help/5126655
10.0.26100.33650 — https://support.microsoft.com/help/5126646
10.0.14393.9612 — https://support.microsoft.com/help/5126868
6.2.9200.26434 — https://support.microsoft.com/help/5126835
6.3.9600.23470 — https://support.microsoft.com/help/5126836

Vulnerabilities 1

High 7.8

CVE-2026-83499

Windows Server Update Service Elevation of Privilege Vulnerability

Insufficient granularity of access control in Windows Server Update Service allows an authorized attacker to elevate privileges locally.

Microsoft Windows Server 2019 Windows Server 2019 (Server Core installation) Windows 10 Version 1809 Windows

Oct 13, 2026

Revision history

2026-10-13 #1
Information published.

References

CVE-2026-83499 Windows Server Update Service Elevation of Privilege Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-83499
Microsoft Exploitability Index
https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1
Microsoft Support Lifecycle
https://support.microsoft.com/lifecycle
Common Vulnerability Scoring System
https://www.first.org/cvss