Heap-Based Buffer Overflow in Microsoft Exchange Server by Microsoft
CVE-2026-55005

8.8HIGH

Key Information:

Vendor

Microsoft
Status
Microsoft Exchange Server 2016 Cumulative Update 23
Microsoft Exchange Server 2019 Cumulative Update 14
Microsoft Exchange Server 2019 Cumulative Update 15
Microsoft Exchange Server Subscription Edition Rtm
Vendor
CVE Published:
14 July 2026

What is CVE-2026-55005?

A heap-based buffer overflow vulnerability in Microsoft Exchange Server permits an authorized attacker to execute arbitrary code remotely. This flaw arises from improper handling of memory buffers, making it critical for organizations using affected versions to implement security patches. Attackers exploiting this vulnerability can gain unauthorized access, potentially compromising sensitive data and network integrity. It is essential to monitor for updates and adopt preventive measures to secure your Exchange environment.

Affected Version(s)

Microsoft Exchange Server 2016 Cumulative Update 23 x64-based Systems 15.01.0.0 < 15.01.2507.071

Microsoft Exchange Server 2019 Cumulative Update 14 x64-based Systems 15.02.0.0 < 15.02.1544.043

Microsoft Exchange Server 2019 Cumulative Update 15 x64-based Systems 15.02.0.0 < 15.02.1748.048

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE...
vendor-advisorypatch

CVSS V3.1

Score:
8.8
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.