Critical CVSS 8.4 EPSS 0.47145 2020-09 archive

Executive Summary

A remote code execution vulnerability exists in Microsoft Exchange server due to improper validation of cmdlet arguments. An attacker who successfully exploited the vulnerability could run arbitrary code in the context of the System user. Exploitation of the vulnerability requires an authenticated user in a certain Exchange role to be compromised. The security update addresses the vulnerability by correcting how Microsoft Exchange handles cmdlet arguments.

Overview

8.4
CVSS HIGH
Critical
MS Severity
Not Exploited
MS Exploit Status
Less Likely
MS Exploit Likelihood
Category Remote Code Execution
Released Sep 8 2020
Last Updated Sep 8 2020
Publicly Disclosed No
CISA KEV Not Listed
Known Exploits None Known
EPSS Score 0.47145 — 0.98685 percentile
NVD CVSS 8.4 HIGH — matches MSRC

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C
ATTACK VECTOR
Network
ATTACK COMPLEXITY
Low
PRIVILEGES REQUIRED
High
USER INTERACTION
Required
SCOPE
Changed
CONFIDENTIALITY
High
INTEGRITY
High
AVAILABILITY
High
EXPLOIT CODE MATURITY
Proof-of-Concept
REMEDIATION LEVEL
Official Fix
REPORT CONFIDENCE
Confirmed
Temporal Score: 7.6

EPSS Score

0.47145
probability of exploitation in the next 30 days
0.98685 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 16 4577352 (Security Update) Critical Remote Code Execution Maybe
Microsoft Exchange Server 2016 Cumulative Update 17 4577352 (Security Update) Critical Remote Code Execution Maybe
Microsoft Exchange Server 2019 Cumulative Update 5 4577352 (Security Update) Critical Remote Code Execution Maybe
Microsoft Exchange Server 2019 Cumulative Update 6 4577352 (Security Update) Critical Remote Code Execution Maybe

Patches

1 patch
Article Type Restart
4577352 Security Update Maybe

Known Exploits

Acknowledgments