Missing Authentication for Critical Function in Microsoft Windows and Windows Server - CVE-2026-83854
Published: October 14, 2026
Vulnerability identifier: #VU155002
CSH Severity: Low
CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-83854
CWE-ID: CWE-306
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to disclose sensitive information.
The vulnerability exists due to improper access control in Windows Notification when accessing toast notifications. A local user can view another user's toast notification content to disclose sensitive information.
The other user must be signed in to the same system.
Affected software
Microsoft Windows
Windows Server
Windows Server
How to mitigate CVE-2026-83854
Install security update from vendor's website.
Microsoft Windows - addressed in versions 10 21H2 10.0.19044.7807, 10 1809 10.0.17763.9376, 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 2019 10.0.17763.9376, 2022 10.0.20348.5761, 2025 10.0.26100.33650
Windows Server - addressed in versions 2019 10.0.17763.9376, 2022 10.0.20348.5761, 2025 10.0.26100.33650