PT-2026-7344 · Microsoft · Windows Http.Sys+1

Matthew Cox · Published 2026-02-10 · Updated 2026-02-10 · CVE-2026-21240

Positive Technologies (AI Summary)

CVSS v3.1

7.8

High

Base vector

AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Name of the Vulnerable Software and Affected Versions Windows HTTP.sys (affected versions not specified)

Description A time-of-check time-of-use (TOCTOU) race condition exists in Windows HTTP.sys. This condition can be exploited by an authorized attacker to gain elevated privileges on a local system. The issue involves a flaw in how the system verifies conditions between the time a check is performed and the time the result of that check is used.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Time Of Check To Time Of Use

Weakness Enumeration

CWE-367

Related Identifiers

BDU:2026-01748

CVE-2026-21240

Affected Products

Windows

Windows Http.Sys

References · 6

• https://bdu.fstec.ru/vul/2026-01748 · Security Note
• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21240 · Vendor Advisory
• http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-21240 · Security Note
• https://msrc.microsoft.com/update-guide/en-US/advisory/CVE-2026-21240 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-21240 · Security Note
• https://osv.dev/vulnerability/CVE-2026-21240 · Vendor Advisory