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Medium · 5.5 Public exploit CVE-2026-2636 EUVD-2026-8718GHSA-fww6-3c6x-rf7p

Denial of Service in Microsoft OS

Published Feb 25, 2026 · Updated Feb 26, 2026 · Assigned by Fortra

Vendor: Microsoft Product: Windows OS Platform: Windows

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.

Affected products

VendorProductAffectedFixed
Microsoft Windows OS < 25H2, ≤ 1123h2 25H2

Public exploits

Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.

Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.

GitHub 2 repositories

  • oxfemale/CVE-2026-2636_PoC ★ 16 · Feb 26, 2026

    **CVE-2026-2636** is a vulnerability in the Windows Common Log File System (CLFS) driver (`CLFS.sys`). An unprivileged user can trigger an unrecoverable system state by calling the `ReadFile` API on …

  • uname1able/CVE-2026-2636 ★ 0 · Mar 5, 2026

Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.

References