CVE Vulnerabilities

CVE-2026-21240

Time-of-check Time-of-use (TOCTOU) Race Condition

Published: Feb 10, 2026 | Modified: Feb 11, 2026
CVSS 3.x
7
HIGH
Source:
NVD
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS 2.x
RedHat/V2
RedHat/V3
Ubuntu
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Time-of-check time-of-use (toctou) race condition in Windows HTTP.sys allows an authorized attacker to elevate privileges locally.

Weakness

The product checks the state of a resource before using that resource, but the resource’s state can change between the check and the use in a way that invalidates the results of the check.

Affected Software

NameVendorStart VersionEnd Version
Windows_10_1809Microsoft*10.0.17763.8389 (excluding)
Windows_10_21h2Microsoft*10.0.19044.6937 (excluding)
Windows_10_22h2Microsoft*10.0.19045.6937 (excluding)
Windows_11_23h2Microsoft*10.0.22631.6649 (excluding)
Windows_11_24h2Microsoft*10.0.26100.7781 (excluding)
Windows_11_25h2Microsoft*10.0.26200.7781 (excluding)
Windows_server_2019Microsoft*10.0.17763.8389 (excluding)
Windows_server_2022Microsoft*10.0.20348.4711 (excluding)
Windows_server_2022_23h2Microsoft*10.0.25398.2149 (excluding)
Windows_server_2025Microsoft*10.0.26100.32313 (excluding)

Potential Mitigations

References