Incorrect authorization in Microsoft Windows and Windows Server - CVE-2026-84011
Published: October 14, 2026
Vulnerability identifier: #VU155083
CSH Severity: Low
CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-84011
CWE-ID: CWE-863
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to bypass network security protections based on fully qualified domain names (FQDNs).
The vulnerability exists due to incorrect authorization in Windows SMB Client when handling network connections subject to domain-based security rules. A local user can exploit the authorization flaw locally to bypass network security protections based on fully qualified domain names.
Affected software
Microsoft Windows
Windows Server
Windows Server
How to mitigate CVE-2026-84011
Install security update from vendor's website.
Microsoft Windows - addressed in versions 11 23H2 10.0.22631.7652, 11 24H2 10.0.26100.9711, 11 25H2 10.0.26200.9711, 11 26H1 10.0.28000.3231
Windows Server - addressed in versions 2022 10.0.20348.5761, 2025 10.0.26100.33650
Windows Server - addressed in versions 2022 10.0.20348.5761, 2025 10.0.26100.33650