Microsoft has urged Windows 10 users to apply an emergency critical security update.

The update for Windows 10 users patches a critical vulnerability, named as SMBGhost or EternalDarkness by various security vendors, that affects the Server Message Block (SMB) network communications protocol. The SMB protocol was also exploited by the NSA-developed EternalBlue during the WannaCry attacks in 2017.

Although Microsoft has not observed an attack exploiting the specific vulnerability, the company recommended that users apply the update to affected devices.

The following versions of Windows 10 are impacted by the vulnerability:

• Windows 10 Version 1903 for 32-bit Systems
• Windows 10 Version 1903 for ARM64-based Systems
• Windows 10 Version 1903 for x64-based Systems
• Windows 10 Version 1909 for 32-bit Systems
• Windows 10 Version 1909 for ARM64-based Systems
• Windows 10 Version 1909 for x64-based Systems
• Windows Server, version 1903 (Server Core installation)
• Windows Server, version 1909 (Server Core installation)