Tampering Vulnerability in Windows Cloud Files Mini Filter Driver by Microsoft
CVE-2026-83991

5.5MEDIUM

Key Information:

Vendor

Microsoft
Status
Windows 10 Version 1809
Windows 10 Version 21h2
Windows 10 Version 22h2
Windows 11 Version 23h2
Vendor
CVE Published:
8 September 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-83991?

The Windows Cloud Files Mini Filter Driver contains a vulnerability due to missing authentication for critical functions. This flaw allows an unauthorized attacker to perform local tampering, which can impact the integrity of files and data within the affected operating systems, such as Windows 10 and Windows Server 2022. It is essential for users and administrators to address this vulnerability promptly to safeguard their systems against potential exploits.

Affected Version(s)

Windows 10 Version 1809 32-bit Systems 10.0.17763.0 < 10.0.17763.9245

Windows 10 Version 21H2 32-bit Systems 10.0.19044.0 < 10.0.19044.7725

Windows 10 Version 22H2 32-bit Systems 10.0.19045.0 < 10.0.19045.7725

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-83991-writeup-and-poc
Created by karollooool

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE...
vendor-advisorypatch

CVSS V3.1

Score:
5.5
Severity:
MEDIUM
Confidentiality:
None
Integrity:
High
Availability:
None
Attack Vector:
Local
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

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