CVE-2026-55005: Microsoft Exchange Server

High severity, CVSS 8.8. EPSS: 1% chance of exploitation in the next 30 days.

Heap-based buffer overflow in Microsoft Exchange Server allows an authorized attacker to execute code over a network.

Affected products

• Microsoft Exchange Server: version 2016 only; version 2019 only
• Microsoft Exchange Server Subscription Edition: before 15.02.2562.045 (fixed in 15.02.2562.045)

Published 2026-07-14. Last modified 2026-07-24.