VulnerabilityAnalyzed
CVE-2026-83999
Improper link resolution before file access ('link following') in Windows Resilient File System (ReFS) Deduplication Service allows an authorized attacker to elevate privileges locally.
HIGH 7.0EPSS 0.21%
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.21%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
Improper link resolution before file access ('link following') in Windows Resilient File System (ReFS) Deduplication Service allows an authorized attacker to elevate privileges locally.
- CVSS 3.1
- 7.0 HIGHCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.21% probability · 11th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-59
- Affected
- microsoft/windows 11 24h2 · microsoft/windows 11 25h2 · microsoft/windows 11 26h1 · microsoft/windows server 2025
- Source
- secure@microsoft.com
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-83999Patch, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.