Critical alert for all Windows 11 users, you must restart your PC immediately

Anyone with a Windows 11 -powered PC would be wise to check their settings and tap the restart button without delay. Microsoft has just released one of its biggest-ever Patch Tuesday updates, which addresses a record-breaking 1,413 vulnerabilities within this popular operating system. What makes this release even more important is that one of the bugs has been given the dreaded 'zero-day' rating.

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That basically means hackers are already aware of the glitch and are actively exploiting it in the wild. As the security experts at Malwarebytes explain, "Tracked as CVE-2026-96951, the security feature it can bypass is the Mark of the Web (MOTW) defense, which can warn users potentially unsafe downloaded files."

This attack is being exploited via specially crafted files that can be designed to take advantage of the vulnerability. These can be easily sent out via emails to Windows 11 users, who are then urged to click and open them.

Another vulnerability to watch is CVE-2026-108398. It's been given a high severity rating of 8.8 out of 10 and affects the .NET Framework and could allow an authorised attacker to bypass Windows Defender Application Control (WDAC) security protections on a local system. This could open the door to unauthorised applications being run on affected devices. The vulnerability was also publicly disclosed before a patch became available.

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This is clearly a big and important update from Microsoft , and it's not a change anyone should ignore if they want to stay safe.

To make sure PCs are protected, Windows 11 users should click the Start button, then open Settings. , select Windows Update (usually at the bottom of the on the left) and click Check for updates.

A list of available changes will then be displayed, and if any are available, a restart will then be required to make sure devices are safe.

Malwarebytes says it's always a good idea to make sure things are fixed.

"After restarting, go back to Windows Update and check again. If it says You’re up to date, you’re all set," the security team said.