Missing Authentication for Critical Function in Microsoft Windows and Windows Server - CVE-2026-42976

Vulnerability identifier: #VU141873

CSH Severity: Low

CVSS v4: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-42976

CWE-ID: CWE-306

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to escalate privileges.

The vulnerability exists due to missing authentication for a critical function in the Windows RPC API when invoking the Remote Access Management service/API RPC server. A local user can call a critical function without proper authentication to escalate privileges.

Successful exploitation could grant SYSTEM privileges.

Microsoft Windows
Windows Server

Install security update from vendor's website.

Microsoft Windows - addressed in versions 10 21H2 10.0.19044.7417, 10 22H2 10.0.19045.7417, 10 1607 10.0.14393.9234, 10 1809 10.0.17763.8880, 11 24H2 10.0.26100.9106, 11 24H2 10.0.26100.9168, 11 25H2 10.0.26200.9168, 11 26H1 10.0.28000.2269
Windows Server - addressed in versions 2012 R2 6.3.9600.23228, 2012 6.2.9200.26132, 2016 10.0.14393.9234, 2019 10.0.17763.8880, 2022 10.0.20348.5440, 2022 10.0.20348.5499, 2025 10.0.26100.32995, 2025 10.0.26100.33222

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2026-42976
• https://support.microsoft.com/help/5120242

• Multiple vulnerabilities in Microsoft Windows