CVE-2026-2636

mediumpriority · track · 10EPSS 0.005 · 40 %ileexploit · PoCEU
grimoire priorityP1 · Urgent
Exploitable?
Public exploit
2 exploits · PoC
Likely / severe?
0.47% (40th) EPSS
CVSS 5.5 · medium
Is it mine?
2 products
Check your exposure
Who says so?
2 sources
cnnvd · enisa_euvd

EPSS · scored 2026-10-27

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.

01

cvss

Technical severity, 0–10. One row per scoring source.

5.5
010

base score 0–10 · higher = more severe · hover a vector to decode

v3.15.5mediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:Hsecondary · ENISA EU
v3.15.5mediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:Hsecondaryexploitability 1.8 · impact 3.6
v3.15.2mediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H/E:Psecondary · CVSS-BT (t0sche)
02

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Trackcoordinatorcisa_ssvcUS
03

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-159US
04

exploits (2)

Public proof-of-concept and weaponised exploit code.

05

affected products (2)

Products and version ranges known to be affected.

06

also known as (3)

Other names and identifiers for this entity.

07

sources

Which sources assert this record, and when.

cnnvdenisa_euvdNVDCVE.orgMITRE
published 2026-02-25modified 2026-06-17
08

references (3)

External citations — patches, advisories, analysis.

scry

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