Improper Authentication in Microsoft Windows and Windows Server - CVE-2025-21349

Vulnerability identifier: #VU103825

CSH Severity: High

CVSS v4: 7.4 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2025-21349

CWE-ID: CWE-287

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to bypass authentication process.

The vulnerability exists due to an error when processing authentication requests in Windows Remote Desktop Configuration Service. A remote attacker can perform a man-in-the-middle (MitM) attack, bypass authentication process and gain unauthorized access to the application.

Microsoft Windows
Windows Server

Install updates from vendor's website.

Microsoft Windows - addressed in versions 10 21H2 10.0.19044.5487, 10 22H2 10.0.19045.5487, 10 1507 10.0.10240.20915, 10 1607 10.0.14393.7785, 10 1809 10.0.17763.6893, 11 22H2 10.0.22621.4890, 11 23H2 10.0.22631.4890, 11 24H2 10.0.26100.3107
Windows Server - addressed in versions 2016 10.0.14393.7785, 2022 23H2 10.0.25398.1425, 2022 10.0.20348.3148, 2022 10.0.20348.3207, 2025 10.0.26100.3107, 2025 10.0.26100.3194

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21349

• Improper Authentication in Microsoft Windows Remote Desktop Configuration Service