Important CVSS 8.8 EPSS 0.00747 2025-10 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
Exploitation Unlikely
MS Exploit Likelihood
Category Elevation of Privilege
Released Oct 14 2025
Last Updated Oct 14 2025
Publicly Disclosed No
CISA KEV Not Listed
Known Exploits None Known
EPSS Score 0.00747 — 0.49986 percentile
NVD CVSS 8.8 HIGH — matches MSRC

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
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

0.00747
probability of exploitation in the next 30 days
0.49986 percentile - updated 2026-06-21
View on FIRST.org

Affected Products

4 affected products
Product KB Article Severity Impact Restart Required
Microsoft Exchange Server 2016 Cumulative Update 23 5066369 (Security Update) Important Elevation of Privilege Yes
Microsoft Exchange Server 2019 Cumulative Update 14 5066368 (Security Update) Important Elevation of Privilege Yes
Microsoft Exchange Server 2019 Cumulative Update 15 5066367 (Security Update) Important Elevation of Privilege Yes
Microsoft Exchange Server Subscription Edition RTM 5066366 (Security Update) Important Elevation of Privilege Yes

Patches

4 patches
Article Type Restart
5066369 Security Update Yes
5066368 Security Update Yes
5066367 Security Update Yes
5066366 Security Update Yes

Known Exploits

Acknowledgments

Justin Hendricks