CVE-2026-70571

Name of the Vulnerable Software and Affected Versions Microsoft Exchange Server 2016 CU23 Microsoft Exchange Server 2019 CU14 Microsoft Exchange Server 2019 CU15 Microsoft Exchange Server Subscription Edition RTM

Description A stack-based buffer overflow exists in the internal content-conversion functionality. This allows an unauthorized remote attacker to execute arbitrary code over a network by sending a specially crafted email. Exploitation requires specific conditions and is characterized by high attack complexity.

Recommendations For Microsoft Exchange Server 2016 CU23, apply security update KB5128898. For Microsoft Exchange Server 2019 CU14, apply security update KB5128897. For Microsoft Exchange Server 2019 CU15, apply security update KB5128896. For Microsoft Exchange Server Subscription Edition RTM, apply security update KB5128895.