Microsoft's June 2026 Patch Tuesday includes a fix for a critical wormable vulnerability in the Windows TCP/IP stack that allows remote code execution with no user interaction required. This is among the most dangerous flaws patched this year.

• What it is: A flaw in how Windows processes IPv6 network traffic allows an attacker to remotely run malicious code on your system.
• Who is affected: All supported Windows versions, including Windows 10, Windows 11, Windows Server 2019, 2022, and 2025. IPv6 is enabled by default on all of these.
• What is the risk: An attacker on the same network segment can compromise a device without any user interaction. Microsoft has rated this vulnerability as wormable, meaning it has the potential to spread automatically from machine to machine across a network.
• What to do: Apply the June 2026 Windows security updates immediately. Verify that automatic updates have run successfully on all devices. If you manage a business network with servers or multiple workstations, treat this as a priority patch this month.

If you are unsure whether your devices are up to date, we recommend contacting your IT provider as soon as possible. Source: Microsoft Security Update Guide - June 2026.