CVE-2025-55687: Windows Resilient File System (ReFS) Elevation of Privilege Vulnerability

Severity: high (CVSS 7.0 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-10-14 · updated 2026-06-17
Weakness: CWE-362

Description

Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Resilient File System (ReFS) allows an unauthorized attacker to elevate privileges locally.

Affected products

Microsoft Windows 10 Version 1507: before 10.0.10240.21161 — fixed in 10.0.10240.21161
Microsoft Windows 10 1607: before 10.0.14393.8519 — fixed in 10.0.14393.8519
Microsoft Windows 10: before 10.0.17763.7919 — fixed in 10.0.17763.7919
Microsoft Windows 10: before 10.0.19044.6456 — fixed in 10.0.19044.6456
Microsoft Windows 10: before 10.0.19045.6456 — fixed in 10.0.19045.6456
Microsoft Windows 11: before 10.0.22621.6060 — fixed in 10.0.22621.6060
Microsoft Windows 11: before 10.0.22631.6060 — fixed in 10.0.22631.6060
Microsoft Windows 11: before 10.0.26100.6899 — fixed in 10.0.26100.6899
Microsoft Windows 11 25H2: before 10.0.26200.6899 — fixed in 10.0.26200.6899
Microsoft Windows Server 2012: r2
Microsoft Windows Server 2016: before 10.0.14393.8519 — fixed in 10.0.14393.8519
Microsoft Windows Server 2019: before 10.0.17763.7919 — fixed in 10.0.17763.7919
Microsoft Windows Server 2022: before 10.0.20348.4294 — fixed in 10.0.20348.4294
Microsoft Windows Server 2022, 23H2 Edition (Server Core installation): before 10.0.25398.1913 — fixed in 10.0.25398.1913
Microsoft Windows Server 2025: before 10.0.26100.6899 — fixed in 10.0.26100.6899
Microsoft Windows 10 Version 1507: from 10.0.10240.0 before 10.0.10240.21161 — fixed in 10.0.10240.21161
Microsoft Windows 10 1607: from 10.0.14393.0 before 10.0.14393.8519 — fixed in 10.0.14393.8519
Microsoft Windows 10: from 10.0.17763.0 before 10.0.17763.7919 — fixed in 10.0.17763.7919
Microsoft Windows 10: from 10.0.19044.0 before 10.0.19044.6456 — fixed in 10.0.19044.6456
Microsoft Windows 10: from 10.0.19045.0 before 10.0.19045.6456 — fixed in 10.0.19045.6456
Microsoft Windows 11: from 10.0.22621.0 before 10.0.22621.6060 — fixed in 10.0.22621.6060
Microsoft Windows 11 version 22H3: from 10.0.22631.0 before 10.0.22631.6060 — fixed in 10.0.22631.6060
Microsoft Windows 11: from 10.0.22631.0 before 10.0.22631.6060 — fixed in 10.0.22631.6060
Microsoft Windows 11: from 10.0.26100.0 before 10.0.26100.6899 — fixed in 10.0.26100.6899
Microsoft Windows 11 25H2: from 10.0.26200.0 before 10.0.26200.6899 — fixed in 10.0.26200.6899
Microsoft Windows Server 2012: from 6.2.9200.0 before 6.2.9200.25722 — fixed in 6.2.9200.25722
Microsoft Windows Server 2012 R2: from 6.3.9600.0 before 6.3.9600.22824 — fixed in 6.3.9600.22824
Microsoft Windows Server 2016: from 10.0.14393.0 before 10.0.14393.8519 — fixed in 10.0.14393.8519
Microsoft Windows Server 2019: from 10.0.17763.0 before 10.0.17763.7919 — fixed in 10.0.17763.7919
Microsoft Windows Server 2022: from 10.0.20348.0 before 10.0.20348.4294 — fixed in 10.0.20348.4294

How to fix

Upgrade to a fixed version: Microsoft Windows 10 Version 1507 10.0.10240.21161; Microsoft Windows 10 1607 10.0.14393.8519; Microsoft Windows 10 10.0.17763.7919; Microsoft Windows 10 10.0.19044.6456; Microsoft Windows 10 10.0.19045.6456; Microsoft Windows 11 10.0.22621.6060; Microsoft Windows 11 10.0.22631.6060; Microsoft Windows 11 10.0.26100.6899; Microsoft Windows 11 25H2 10.0.26200.6899; Microsoft Windows Server 2016 10.0.14393.8519; Microsoft Windows Server 2019 10.0.17763.7919; Microsoft Windows Server 2022 10.0.20348.4294. Check the vendor advisory for mitigations.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-55687

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