Important CVSS 8.8 2026-10 archive

Executive Summary

Weak authentication in Microsoft Exchange Server allows an authorized attacker to elevate privileges over a network.

Overview

8.8
CVSS HIGH
Important
MS Severity
Not Exploited
MS Exploit Status
More Likely
MS Exploit Likelihood
Category Elevation of Privilege
Released Oct 13 2026
Last Updated Oct 13 2026
Publicly Disclosed No
CISA KEV Not Listed
Known Exploits None Known

CVSS Vector

ATTACK VECTOR
Network
ATTACK COMPLEXITY
Low
PRIVILEGES REQUIRED
Low
USER INTERACTION
None
SCOPE
Unchanged
CONFIDENTIALITY
High
INTEGRITY
High
AVAILABILITY
High
EXPLOIT CODE MATURITY
Unproven
REMEDIATION LEVEL
Official Fix
REPORT CONFIDENCE
Confirmed
Temporal Score: 7.7

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 5129958 (Security Update) Important Elevation of Privilege No
Microsoft Exchange Server 2019 Cumulative Update 14 5129957 (Security Update) Important Elevation of Privilege No
Microsoft Exchange Server 2019 Cumulative Update 15 5129956 (Security Update) Important Elevation of Privilege No
Microsoft Exchange Server Subscription Edition RTM 5129955 (Security Update) Important Elevation of Privilege No

Patches

4 patches
Article Type Restart
5129958 Security Update No
5129957 Security Update No
5129956 Security Update No
5129955 Security Update No

Exploits & PoC

Detection Rules

Acknowledgments

Jan Mitchell from Microsoft