Winsage
July 11, 2025
Microsoft has replaced the default scripting engine JScript with JScript9Legacy in Windows 11, version 24H2 and beyond to enhance security against web threats, particularly cross-site scripting (XSS) vulnerabilities. JScript, which has been in use since 1996, has become outdated and non-compliant with modern security standards. JScript9Legacy is designed to meet legacy scripting needs while improving security and compatibility. The transition to JScript9Legacy will occur automatically for users, and existing scripts should continue to function without disruption. If compatibility issues arise, users can revert to the previous engine with support from Microsoft.