Microsoft Exchange Servers Left Exposed by Critical Security Flaw

Nearly 22,000 Microsoft Exchange servers remain exposed to a critical security flaw in the United States and Germany.

The vulnerability, known as CVE-2026-62911, allows an authorized attacker to elevate privileges over a network. Microsoft released a fix for this issue on August 11, 2026.

The National Cyber Security Centre of the Netherlands (NCSC-NL) has warned that a working exploit for the vulnerability is now circulating online.

The NCSC-NL advised organizations to install security updates as soon as possible and replace outdated versions of Exchange Server if necessary. The centre also suggested contacting an IT administrator or service provider for assistance in identifying the version of Exchange Server being used.