CVE-2026-21250

Windows HTTP.sys Elevation of Privilege Vulnerability

State: Published
Severity: 7.8 High
Published: Feb 10, 2026
Updated: Aug 19, 2026
Reserved: Dec 11, 2025

Description

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

Scores

CVSS	Score	Vector	Source
3.1	7.8 High	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C	microsoft

Weaknesses

CWE-822 Untrusted Pointer Dereference

Affected Products

Product	Versions
Windows 11 Version 24H2Microsoft	10.0.26100.0 to before 10.0.26100.7840Affected
Windows 11 Version 25H2Microsoft	10.0.26200.0 to before 10.0.26200.7840Affected
Windows 11 version 26H1Microsoft	10.0.28000.0 to before 10.0.28000.1575Affected
Windows 11 Version 26H1Microsoft	10.0.28000.0 to before 10.0.28000.1575Affected
Windows Server 2022, 23H2 Edition (Server Core installation)Microsoft	10.0.25398.0 to before 10.0.25398.2149Affected
Windows Server 2025Microsoft	10.0.26100.0 to before 10.0.26100.32370Affected
Windows Server 2025 (Server Core installation)Microsoft	10.0.26100.0 to before 10.0.26100.32370Affected

References

Windows HTTP.sys Elevation of Privilege Vulnerabilityvendor-advisorypatch

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