CVE-2026-83999

HIGH

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 v3.1 Score

7.0
HIGH
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack Vector
LOCAL
Complexity
HIGH
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Published: 9/8/2026Modified: 9/11/2026

Related Intelligence (1)

CRITICALRansomware

Patch Tuesday - September 2026

Microsoft is publishing 974 own-product vulnerabilities on September 2026 Patch Tuesday , including 723 vulnerabilities in Windows. Along with Microsoft fixes for 25 non-Microsoft CVEs, that brings the total number of vulnerabilities on the table today to 999. Whether this is the biggest Patch Tuesday ever depends on how we count, but this is by far the most CVEs that Microsoft has ever published

CVE-2026-85880CVE-2026-81963
Rapid7

References (1)

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-83999PatchVendor Advisory