Nearly 22,000 Microsoft Exchange servers remain exposed to critical security flaw (CVE-2026-62911)

Nearly 22,000 Microsoft Exchange servers remain unpatched against CVE-2026-62911, a critical authentication bypass vulnerability, according to daily scans from the Shadowserver Foundation. The United States and Germany top the list with 6,200 and 5,100 unpatched servers. CVE-2026-62911 is a critical severity vulnerability, and Microsoft describes it as “authentication bypass by capture-replay in Microsoft Exchange Server,” which allows an authorized attacker to elevate privileges over a network.

Original reporting by Help Net Security · Sinisa Markovic. GridIndex is an aggregation and intelligence layer — full credit to the original publisher.