Access Control Vulnerability in Microsoft Exchange Server
CVE-2026-55006

7.8HIGH

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-2026-55006?

An access control vulnerability in Microsoft Exchange Server could allow an authorized attacker to escalate their privileges on the system. This flaw arises from insufficient granularity in the access control mechanism. By exploiting this vulnerability, an attacker could gain unauthorized access to sensitive resources or functions that should be protected. Organizations using affected versions of Microsoft Exchange Server must prioritize timely updates and patches to mitigate risks associated with this vulnerability.

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:
7.8
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Local
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.