CVE-2026-2636

MEDIUM EPSS 32.8%

Published Feb 25, 20264mo ago · Modified Jun 17, 20262w ago

5.5 CVSS 3.1

Medium

Published Feb 25, 2026 4mo ago

Last Modified Jun 17, 2026 2w ago

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.

CVSS Details

Base Score

5.5

Exploitability

1.8

Impact

3.6

Vector string

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

Attack Vector Local

Attack Complexity Low

Privileges Required Low

User Interaction None

Scope Unchanged

Confidentiality None

Integrity None

Availability High

Threat Intelligence

EPSS Exploit Probability

32.8% percentile

Exploit & Patch Status

No Known Exploit

No Patch Available

Weaknesses 1

CWE-159

References 1

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

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.