Microsoft's June 2026 Patch Tuesday, released on 10 June, is the largest in the program's 23-year history. It addresses 200 vulnerabilities, including six zero-days and 33 rated Critical. If your organisation's Windows devices haven't applied this update yet, it should be treated as an immediate priority.

• What's affected: Windows, Microsoft Office (including Outlook and Word), Remote Desktop Client, and Hyper-V are among the components with Critical-rated patches. Remote Desktop Client alone had 11 CVEs patched this month, including four Critical ones.
• Zero-days to be aware of: Six publicly known vulnerabilities were addressed, including flaws in Outlook and Word that can be triggered by opening a malicious document or email attachment. Hyper-V patches address guest-escape vulnerabilities that could allow an attacker to move from a virtual machine to the underlying host server.
• Exchange Server: Microsoft also released separate Exchange Server security updates for June. On-premises Exchange environments require these to be applied independently of standard Windows Updates.
• Microsoft 365 (cloud): Businesses using cloud-based Microsoft 365 have already received automatic updates for cloud components. However, Windows devices in your organisation still need the June 2026 patches applied locally.
• Who is affected: Any business running Windows computers, Microsoft Office, or on-premises Microsoft server infrastructure.

We recommend confirming with your IT provider that June 2026 patches have been deployed across all devices. (Source: BleepingComputer, Microsoft Security Response Center)