Elevation of Privileges in Microsoft Exchange Server by Microsoft
CVE-2026-87696

7.5HIGH

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:
13 October 2026

What is CVE-2026-87696?

An improper verification of cryptographic signature flaw in Microsoft Exchange Server allows authorized attackers to elevate their privileges over the network. By exploiting this vulnerability, attackers can gain unauthorized access to sensitive data and perform actions that exceed their intended permission levels, posing a significant risk to organizational security.

Affected Version(s)

Microsoft Exchange Server 2016 Cumulative Update 23 x64-based Systems 15.01.0.0 < 15.01.2507.077

Microsoft Exchange Server 2019 Cumulative Update 14 x64-based Systems 15.02.0.0 < 15.02.1544.050

Microsoft Exchange Server 2019 Cumulative Update 15 x64-based Systems 15.02.0.0 < 15.02.1748.055

References

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

CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
High
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.