CVE-2026-21240
Windows HTTP.sys Elevation of Privilege Vulnerability
CVSS Score
7.8
EPSS Score
0.0%
EPSS Percentile
8th
Time-of-check time-of-use (toctou) race condition in Windows HTTP.sys allows an authorized attacker to elevate privileges locally.
| Vendor | microsoft |
| Product | windows 10 version 1809 |
| Ecosystems | |
| Industries | TechnologyEnterprise |
| Published | Feb 10, 2026 |
| Last Updated | Apr 10, 2026 |
Stay Ahead of the Next One
Get instant alerts for microsoft windows 10 version 1809
Be the first to know when new high vulnerabilities affecting microsoft windows 10 version 1809 are published — delivered to Slack, Telegram or Discord.
Get Free Alerts →
Free · No credit card · 60 sec setup
CVSS v3 Breakdown
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 Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality
Integrity
Availability
Affected Versions
Microsoft / Windows 10 Version 1809
10.0.17763.0 < 10.0.17763.8389
Microsoft / Windows 10 Version 21H2
10.0.19044.0 < 10.0.19044.6937
Microsoft / Windows 10 Version 22H2
10.0.19045.0 < 10.0.19045.6937
Microsoft / Windows 11 version 22H3
10.0.22631.0 < 10.0.22631.6649
Microsoft / Windows 11 Version 23H2
10.0.22631.0 < 10.0.22631.6649
Microsoft / Windows 11 Version 24H2
10.0.26100.0 < 10.0.26100.7840
Microsoft / Windows 11 Version 25H2
10.0.26200.0 < 10.0.26200.7840
Microsoft / Windows 11 version 26H1
10.0.28000.0 < 10.0.28000.1575
Microsoft / Windows 11 Version 26H1
10.0.28000.0 < 10.0.28000.1575
Microsoft / Windows Server 2019
10.0.17763.0 < 10.0.17763.8389
Microsoft / Windows Server 2019 (Server Core installation)
10.0.17763.0 < 10.0.17763.8389
Microsoft / Windows Server 2022
10.0.20348.0 < 10.0.20348.4773
Microsoft / Windows Server 2022, 23H2 Edition (Server Core installation)
10.0.25398.0 < 10.0.25398.2149
Microsoft / Windows Server 2025
10.0.26100.0 < 10.0.26100.32370
Microsoft / Windows Server 2025 (Server Core installation)
10.0.26100.0 < 10.0.26100.32370