CVE-2026-83586

Weak authentication in Windows Resilient File System (ReFS) Deduplication Service allows an…

Risk score: 51/100
CVSS: 7.8 v3.1
Exploit chance (30 days): 0.3%
Published: 13 Oct 2026

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What to know

What it is: Weak authentication in Windows Resilient File System (ReFS) Deduplication Service allows an authorized attacker to elevate privileges locally.
Affected: See advisory
Fix: Apply the vendor's security update; see the linked advisory.
Exploitation: No known exploitation

Why it is Yellow

CVSS 7.8 high

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-83586

Original description

Weak authentication in Windows Resilient File System (ReFS) Deduplication Service allows an authorized attacker to elevate privileges locally.

Last activity 13 Oct 2026. Patch Forecast updates every hour.