Protection Mechanism Failure in Windows and Windows Server - CVE-2026-21510
Published: February 10, 2026
Vulnerability identifier: #VU122544
CSH Severity: Critical
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:A/U:Red
CVE-ID: CVE-2026-21510
CWE-ID: CWE-693
Exploitation vector: Remote access
Exploit availability:
The vulnerability is being exploited in the wild
Vendor: Microsoft
Affected software:
Windows
Windows Server
Windows
Windows Server
Detailed vulnerability description
The vulnerability allows a remote attacker to bypass implemented security restrictions.
The vulnerability exists due to insufficient implementation of security measures. An attacker can trick the victim into clicking on a specially crafted URL or shortcut file to bypass Windows SmartScreen and Windows Shell security prompts and execute arbitrary code on the system.
Note, the vulnerability is being actively exploited in the wild.
How to mitigate CVE-2026-21510
Install updates from vendor's website.