CVE-2025-21271: Windows Cloud Files Mini Filter Driver Elevation of Privilege Vulnerability

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-01-14 · updated 2026-06-17
Weakness: CWE-126

Description

Windows Cloud Files Mini Filter Driver Elevation of Privilege Vulnerability

Affected products

Microsoft Windows 10: before 10.0.17763.6775 — fixed in 10.0.17763.6775
Microsoft Windows 10: before 10.0.19044.5371 — fixed in 10.0.19044.5371
Microsoft Windows 10: before 10.0.19045.5371 — fixed in 10.0.19045.5371
Microsoft Windows Server 2019: before 10.0.17763.6775 — fixed in 10.0.17763.6775
Microsoft Windows Server 2022: before 10.0.20348.3091 — fixed in 10.0.20348.3091
Microsoft Windows 10: from 10.0.17763.0 before 10.0.17763.6775 — fixed in 10.0.17763.6775
Microsoft Windows 10: from 10.0.19044.0 before 10.0.19044.5371 — fixed in 10.0.19044.5371
Microsoft Windows 10: from 10.0.19045.0 before 10.0.19045.5371 — fixed in 10.0.19045.5371
Microsoft Windows Server 2019: from 10.0.17763.0 before 10.0.17763.6775 — fixed in 10.0.17763.6775
Microsoft Windows Server 2022: from 10.0.20348.0 before 10.0.20348.3091 — fixed in 10.0.20348.3091

How to fix

Upgrade to a fixed version: Microsoft Windows 10 10.0.17763.6775; Microsoft Windows 10 10.0.19044.5371; Microsoft Windows 10 10.0.19045.5371; Microsoft Windows Server 2019 10.0.17763.6775; Microsoft Windows Server 2022 10.0.20348.3091; Microsoft Windows 10 10.0.17763.6775; Microsoft Windows 10 10.0.19044.5371; Microsoft Windows 10 10.0.19045.5371; Microsoft Windows Server 2019 10.0.17763.6775; Microsoft Windows Server 2022 10.0.20348.3091. Check the vendor advisory for mitigations.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21271

Get alerted when CVE-2025-21271 or the next vulnerability affects your stack