Editing Windows NT 4.0 (section)

==Security==
Microsoft stopped providing security updates for Windows NT 4.0 Workstation on June 30, 2004, Windows NT 4.0 Server on December 31, 2004, and Windows NT 4.0 Embedded on July 11, 2006, due to major security flaws including [https://docs.microsoft.com/en-us/security-updates/securitybulletins/2003/ms03-010 Microsoft Security Bulletin MS03-010], which according to Microsoft could not be patched without significant changes to the core operating system. According to the security bulletin, "Due to the fundamental differences between Windows NT 4.0 and Windows 2000 and its successors, it is infeasible to rebuild the software for Windows NT 4.0 to eliminate the vulnerability. To do so would require re-architecting a very significant amount of the Windows NT 4.0 operating system, and there would be no assurance that applications designed to run on Windows NT 4.0 would continue to operate on the patched system."

Between June 2003 and June 2007, 127 security flaws were identified and patched in Windows 2000 Server, many of which may also affect Windows NT 4.0 Server; however, Microsoft does not test security bulletins against unsupported software.