Stack-based buffer overflow in Microsoft Exchange Server and Microsoft Exchange Server Subscription Edition RTM - CVE-2026-70571
Published: October 14, 2026
Vulnerability identifier: #VU154954
CSH Severity: High
CVSS v4: 9.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-70571
CWE-ID: CWE-121
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to execute arbitrary code on the server.
The vulnerability exists due to a stack-based buffer overflow in the internal content-conversion process of Microsoft Exchange Server when processing specially crafted emails. A remote attacker can send a specially crafted email to an affected server to execute arbitrary code on the server.
User interaction is not required. Successful exploitation requires a deep understanding of the target environment and depends on environmental factors, system configuration, and additional security measures.
Affected software
Microsoft Exchange Server
Microsoft Exchange Server Subscription Edition RTM
Microsoft Exchange Server Subscription Edition RTM
How to mitigate CVE-2026-70571
Install security update from vendor's website.
Microsoft Exchange Server - addressed in versions 15.01.2507.077, 15.02.1544.050, 15.02.1748.055
Microsoft Exchange Server Subscription Edition RTM - update to 15.02.2562.056
Microsoft Exchange Server Subscription Edition RTM - update to 15.02.2562.056