Serious vulnerability threatens tens of thousands of Exchange servers

A serious vulnerability was recently discovered in Exchange Server 2016, Exchange Server 2016, and Exchange Server Subscription Edition (SE). The vulnerability is designated CVE-2026-62911 and can be exploited by hackers to gain full access to affected systems, according to Bleeping Computer.

Microsoft has released security patches to address the vulnerability as part of its August 2026 Patch Tuesday release, but there are still 21,899 unpatched servers at risk, according to The Shadowserver Foundation. The highest concentrations of vulnerable servers are in the US and Germany, the security group said.

The Netherlands National Cyber Security Centre and other agencies have urged admins to install the latest patches as soon as possible.

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AndyC

Andy Curtis is an award-winning security consultant, researcher and public speaker. He has been working in the computer security industry since the early 1990s, having been employed by state and federal government, leading healthcare and banking providers across three continents. He has given talks about computer security for some of the world’s largest companies, worked with law enforcement agencies on investigations into hacking groups, and is a regular voice on TV and radio explaining IT security threats.

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