Spoofing attack in Microsoft Windows and Windows Server - CVE-2025-9491

Vulnerability identifier: #VU105851

CSH Severity: High

CVSS v4: 7.1 [CVSS:4.0/AV:L/AC:H/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2025-9491

CWE-ID: CWE-451

Exploitation vector: Remote access

Exploit availability: The vulnerability is being exploited in the wild

The vulnerability allows a remote attacker to perform spoofing attack.

The vulnerability exists due to incorrect processing of user-supplied data in .lnk files. A remote attacker can hide command line arguments inside an .lnk file, trick the victim into opening it and execute arbitrary code with privileges of the current user.

Note, the vulnerability is being actively exploited in the wild.

Microsoft Windows
Windows Server

Install update from vendor's website.

Microsoft Windows - addressed in versions 10 21H2 10.0.19044.6575, 10 22H2 10.0.19045.6575, 10 1607 10.0.14393.8594, 10 1809 10.0.17763.8027, 11 23H2 10.0.22631.6199, 11 24H2 10.0.26100.7092, 11 24H2 10.0.26100.7171, 11 25H2 10.0.26200.7092, 11 25H2 10.0.26200.7171
Windows Server - addressed in versions 2008 R2 6.1.7601.28021, 2008 6.0.6003.23624, 2012 R2 6.3.9600.22869, 2012 6.2.9200.25768, 2016 10.0.14393.8594, 2019 10.0.17763.8027, 2022 23H2 10.0.25398.1965, 2022 10.0.20348.4346, 2022 10.0.20348.4405, 2025 10.0.26100.7092, 2025 10.0.26100.7171

• Exploit #12265 - CVE-2025-9491_POC (January 9, 2026)

• https://www.zerodayinitiative.com/advisories/ZDI-25-148/
• https://www.trendmicro.com/en_us/research/25/c/windows-shortcut-zero-day-exploit.html
• https://msrc.microsoft.com/update-guide/advisory/ADV25258226
• https://blog.0patch.com/2025/12/microsoft-silently-patched-cve-2025.html

• Remote code execution via misrepresented LNK file in Microsoft Windows