Starting with Windows 11 version 24H2, Microsoft has enabled the JScript9Legacy scripting engine by default, replacing the older JScript. This upgrade boosts security and performance, aligning with modern web standards to better protect users from web-based attacks without requiring any user action. Unique :

JScript9Legacy Now Default in Windows 11 24H2: What You Need to Know

Microsoft just flipped the switch on a key scripting engine update in Windows 11, version 24H The JScript9Legacy engine is now enabled by default, replacing the older JScript engine. This change aims to boost security and performance for all scripting tasks on the platform. If you’re a developer or IT pro, here’s a quick rundown of what’s new and why it matters.

What’s New with JScript9Legacy?

Built on JScript9, the new JScript9Legacy scripting engine offers enhanced security and better compatibility with modern web standards. This upgrade helps reduce vulnerabilities like cross-site scripting (XSS) attacks. Microsoft replaced the old JScript.dll with JScript9Legacy.dll, introducing stricter execution policies and improved JavaScript object handling.

“The new engine incorporates advanced security features such as improved handling of JavaScript objects and stricter execution policies.”

In short, JScript9Legacy is designed to make scripting safer and more efficient on Windows 11, version 24H2 and beyond.

Major Updates and Impact

This update only affects Windows 11, version 24H2 and newer. Older Windows versions won’t see any changes or impacts from this switch. All existing scripts using JScript will now run through JScript9Legacy automatically, without any need for manual intervention.

Microsoft assures users that workflows won’t break due to this change. If you rely on scripting in your IT environment, you can continue as usual without worrying about compatibility issues.

Rolling Back If Needed

In the rare case of incompatibility, Microsoft provides a rollback option. Users can contact Microsoft support via the Services Hub for guidance on reverting to the original JScript engine.

“No additional action is required from you to benefit from JScript9Legacy, nor will it impact existing workflows.”

Stay Connected and Supported

To keep up with best practices and ongoing updates, bookmark the Windows Tech Community. Follow @MSWindowsITPro on X and LinkedIn for the latest insights. For direct support, Microsoft Q&A remains a great resource.

Overall, this update is a smart move by Microsoft to tighten security and modernize scripting on Windows 1 If you’re managing Windows environments, it’s worth knowing that JScript9Legacy is now your new default scripting engine.

 

• JScript9Legacy enhances security by mitigating cross-site scripting (XSS) risks and enforcing stricter execution policies.
• The new engine replaces JScript.dll with JScript9Legacy.dll for improved system defense against malicious scripts.
• This update applies solely to Windows 11, version 24H2 and later; earlier Windows versions remain unaffected.
• No additional steps are needed from users or IT admins to benefit from the new scripting engine.
• Users facing compatibility issues can contact Microsoft support to roll back to the original JScript engine.

 

From the Windows IT Pro Blog articles

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