MSRC-CVE-2026-21250 — Windows HTTP.sys Elevation of Privilege Vulnerability

Summary

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

Details

What privileges could be gained by an attacker who successfully exploited this vulnerability?
An attacker who successfully exploited this vulnerability could gain SYSTEM privileges.

Security updates
10.0.26100.32370 — https://support.microsoft.com/help/5075899
10.0.26100.32313 — https://support.microsoft.com/help/5075942
10.0.26200.7840 — https://support.microsoft.com/help/5077181
10.0.26200.7781 — https://support.microsoft.com/help/5077212
10.0.25398.2149 — https://support.microsoft.com/help/5075897
10.0.28000.1575 — https://support.microsoft.com/help/5077179

Vulnerabilities 1

High 7.8

CVE-2026-21250 Public exploit

Windows HTTP.sys Elevation of Privilege Vulnerability

Untrusted pointer dereference in Windows HTTP.sys allows an authorized attacker to elevate privileges locally.

Microsoft Windows Server 2025 Windows Server 2025 (Server Core installation) Windows 11 Version 24H2 Windows

Feb 10, 2026

Revision history

2026-02-10 #1
Information published.

References

CVE-2026-21250 Windows HTTP.sys Elevation of Privilege Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21250
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