Important CVSS 9.1 2026-09 archive

Executive Summary

Missing authorization in Microsoft Exchange Server allows an authorized attacker to elevate privileges over a network.

Overview

9.1
CVSS CRITICAL
Important
MS Severity
Not Exploited
MS Exploit Status
Less Likely
MS Exploit Likelihood
Category Elevation of Privilege
Released Sep 8 2026
Last Updated Sep 8 2026
Publicly Disclosed No
CISA KEV Not Listed
Known Exploits None Known

CVSS Vector

ATTACK VECTOR
Network
ATTACK COMPLEXITY
Low
PRIVILEGES REQUIRED
High
USER INTERACTION
None
SCOPE
Changed
CONFIDENTIALITY
High
INTEGRITY
High
AVAILABILITY
High
EXPLOIT CODE MATURITY
Unproven
REMEDIATION LEVEL
Official Fix
REPORT CONFIDENCE
Confirmed
Temporal Score: 7.9

EPSS Score

No EPSS score available for this CVE.

View on FIRST.org

Affected Products

4 affected products
Product KB Article Severity Impact Restart Required
Microsoft Exchange Server 2016 Cumulative Update 23 5121611 (Security Update) Important Elevation of Privilege Yes
Microsoft Exchange Server 2019 Cumulative Update 14 5121610 (Security Update) Important Elevation of Privilege Yes
Microsoft Exchange Server 2019 Cumulative Update 15 5121609 (Security Update) Important Elevation of Privilege Yes
Microsoft Exchange Server Subscription Edition RTM 5121608 (Security Update) Important Elevation of Privilege Yes

Patches

4 patches
Article Type Restart
5121611 Security Update Yes
5121610 Security Update Yes
5121609 Security Update Yes
5121608 Security Update Yes

Exploits & PoC

Detection Rules

Acknowledgments

Bui Xuan Quang (buxu) with Ncsgroup.vn
Anonymous