CVE-2026-2636

Published: Feb 25, 2026Modified: Jun 17, 2026Deferred

5.5

Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Exploitability: 1.8 / Impact: 3.6

Source: df4dee71-de3a-4139-9588-11b62fe6c0ff (Secondary)

Description

This vulnerability is caused by a CWE‑159: "Improper Handling of Invalid Use of Special Elements" weakness, which leads to an unrecoverable inconsistency in the CLFS.sys driver. This condition forces a call to the KeBugCheckEx function, allowing an unprivileged user to trigger a system crash. Microsoft silently fixed this vulnerability in the September 2025 cumulative update for Windows 11 2024 LTSC and Windows Server 2025. Windows 25H2 (released in September) was released with the patch. Windows 1123h2 and earlier versions remain vulnerable.

Related CWEs

CWE-159

Improper Handling of Invalid Use of Special Elements

The product does not properly filter, remove, quote, or otherwise manage the invalid use of special elements in user-controlled input, which could cause adverse effect on its behavior and integrity.

References (1)

https://www.fortra.com/security/advisories/research/fr-2026-001

Source: df4dee71-de3a-4139-9588-11b62fe6c0ff

Timeline

No history available yet.