CVE-2026-70571: microsoft microsoft exchange server 2016 cumulative update 23 Stack-based Buffer Overflow

Vulnerability summary

CVE-2026-70571 is a high (CVSS 8.1) Stack-based Buffer Overflow vulnerability in microsoft microsoft exchange server 2016 cumulative update 23. EPSS estimates a 0.93% chance of exploitation in the next 30 days, higher than 59.8% of scored vulnerabilities.

Timeline

1. 13-10-2026
   PublishedVulnerability first disclosed.
2. 20-10-2026
   Last modifiedVulnerability information updated.

Description

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

• CWE-121Stack-based Buffer OverflowA stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).